What is the JavaScript equivalent of var_dump or print_r in PHP?

Question

I would like to see the structure of object in JavaScript (for debugging). Is there anything similar to var_dump in PHP?

Solution 1

Most modern browsers have a console in their developer tools, useful for this sort of debugging.

console.log(myvar);

Then you will get a nicely mapped out interface of the object/whatever in the console.

Check out the console documentation for more details.

Solution 2

Most common way:

console.log(object);

However I must mention JSON.stringify which is useful to dump variables in non-browser scripts:

console.log( JSON.stringify(object) );

The JSON.stringify function also supports built-in prettification as pointed out by Simon Zyx.

Example:

var obj = {x: 1, y: 2, z: 3};

console.log( JSON.stringify(obj, null, 2) ); // spacing level = 2

The above snippet will print:

{
  "x": 1,
  "y": 2,
  "z": 3
}

On caniuse.com you can view the browsers that support natively the JSON.stringify function: http://caniuse.com/json

You can also use the Douglas Crockford library to add JSON.stringify support on old browsers: https://github.com/douglascrockford/JSON-js

Docs for JSON.stringify: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify

I hope this helps :-)

Solution 3

I wrote this JS function dump() to work like PHP's var_dump(). To show the contents of the variable in an alert window: dump(variable) To show the contents of the variable in the web page: dump(variable, 'body') To just get a string of the variable: dump(variable, 'none')

/* repeatString() returns a string which has been repeated a set number of times */
function repeatString(str, num) {
    out = '';
    for (var i = 0; i < num; i++) {
        out += str;
    }
    return out;
}

/*
dump() displays the contents of a variable like var_dump() does in PHP. dump() is
better than typeof, because it can distinguish between array, null and object.
Parameters:
    v:              The variable
    howDisplay:     "none", "body", "alert" (default)
    recursionLevel: Number of times the function has recursed when entering nested
                    objects or arrays. Each level of recursion adds extra space to the
                    output to indicate level. Set to 0 by default.
Return Value:
    A string of the variable's contents
Limitations:
    Can't pass an undefined variable to dump(). 
    dump() can't distinguish between int and float.
    dump() can't tell the original variable type of a member variable of an object.
    These limitations can't be fixed because these are *features* of JS. However, dump()
*/
function dump(v, howDisplay, recursionLevel) {
    howDisplay = (typeof howDisplay === 'undefined') ? "alert" : howDisplay;
    recursionLevel = (typeof recursionLevel !== 'number') ? 0 : recursionLevel;

    var vType = typeof v;
    var out = vType;

    switch (vType) {
        case "number":
        /* there is absolutely no way in JS to distinguish 2 from 2.0
           so 'number' is the best that you can do. The following doesn't work:
           var er = /^[0-9]+$/;
           if (!isNaN(v) && v % 1 === 0 && er.test(3.0)) {
               out = 'int';
           }
        */
        break;
    case "boolean":
        out += ": " + v;
        break;
    case "string":
        out += "(" + v.length + '): "' + v + '"';
        break;
    case "object":
        //check if null
        if (v === null) {
            out = "null";
        }
        //If using jQuery: if ($.isArray(v))
        //If using IE: if (isArray(v))
        //this should work for all browsers according to the ECMAScript standard:
        else if (Object.prototype.toString.call(v) === '[object Array]') {
            out = 'array(' + v.length + '): {\n';
            for (var i = 0; i < v.length; i++) {
                out += repeatString('   ', recursionLevel) + "   [" + i + "]:  " +
                    dump(v[i], "none", recursionLevel + 1) + "\n";
            }
            out += repeatString('   ', recursionLevel) + "}";
        }
        else {
            //if object
            let sContents = "{\n";
            let cnt = 0;
            for (var member in v) {
                //No way to know the original data type of member, since JS
                //always converts it to a string and no other way to parse objects.
                sContents += repeatString('   ', recursionLevel) + "   " + member +
                    ":  " + dump(v[member], "none", recursionLevel + 1) + "\n";
                cnt++;
            }
            sContents += repeatString('   ', recursionLevel) + "}";
            out += "(" + cnt + "): " + sContents;
        }
        break;
    default:
        out = v;
        break;
    }

    if (howDisplay == 'body') {
        var pre = document.createElement('pre');
        pre.innerHTML = out;
        document.body.appendChild(pre);
    }
    else if (howDisplay == 'alert') {
        alert(out);
    }

    return out;
}

Solution 4

The var_dump equivalent in JavaScript? Simply, there isn't one.

But, that doesn't mean you're left helpless. Like some have suggested, use Firebug (or equivalent in other browsers), but unlike what others suggested, don't use console.log when you have a (slightly) better tool console.dir:

console.dir(object)

Prints an interactive listing of all properties of the object. This looks identical to the view that you would see in the DOM tab.

Solution 5

As others have already mentioned, the best way to debug your variables is to use a modern browser's developer console (e.g. Chrome Developer Tools, Firefox+Firebug, Opera Dragonfly _{(which now disappeared in the new Chromium-based (Blink) Opera, but as developers say, "Dragonfly is not dead though we cannot give you more information yet")}.

But in case you need another approach, there's a really useful site called php.js:

http://phpjs.org/

which provides "JavaScript alternatives to PHP functions" - so you can use them the similar way as you would in PHP. I will copy-paste the appropriate functions to you here, BUT be aware that these codes can get updated on the original site in case some bugs are detected, so I suggest you visiting the phpjs.org site! (Btw. I'm NOT affiliated with the site, but I find it extremely useful.)

var_dump() in JavaScript

Here is the code of the JS-alternative of var_dump():
http://phpjs.org/functions/var_dump/
it depends on the echo() function: http://phpjs.org/functions/echo/

function var_dump() {
  //  discuss at: http://phpjs.org/functions/var_dump/
  // original by: Brett Zamir (http://brett-zamir.me)
  // improved by: Zahlii
  // improved by: Brett Zamir (http://brett-zamir.me)
  //  depends on: echo
  //        note: For returning a string, use var_export() with the second argument set to true
  //        test: skip
  //   example 1: var_dump(1);
  //   returns 1: 'int(1)'

  var output = '',
    pad_char = ' ',
    pad_val = 4,
    lgth = 0,
    i = 0;

  var _getFuncName = function(fn) {
    var name = (/\W*function\s+([\w\$]+)\s*\(/)
      .exec(fn);
    if (!name) {
      return '(Anonymous)';
    }
    return name[1];
  };

  var _repeat_char = function(len, pad_char) {
    var str = '';
    for (var i = 0; i < len; i++) {
      str += pad_char;
    }
    return str;
  };
  var _getInnerVal = function(val, thick_pad) {
    var ret = '';
    if (val === null) {
      ret = 'NULL';
    } else if (typeof val === 'boolean') {
      ret = 'bool(' + val + ')';
    } else if (typeof val === 'string') {
      ret = 'string(' + val.length + ') "' + val + '"';
    } else if (typeof val === 'number') {
      if (parseFloat(val) == parseInt(val, 10)) {
        ret = 'int(' + val + ')';
      } else {
        ret = 'float(' + val + ')';
      }
    }
    // The remaining are not PHP behavior because these values only exist in this exact form in JavaScript
    else if (typeof val === 'undefined') {
      ret = 'undefined';
    } else if (typeof val === 'function') {
      var funcLines = val.toString()
        .split('\n');
      ret = '';
      for (var i = 0, fll = funcLines.length; i < fll; i++) {
        ret += (i !== 0 ? '\n' + thick_pad : '') + funcLines[i];
      }
    } else if (val instanceof Date) {
      ret = 'Date(' + val + ')';
    } else if (val instanceof RegExp) {
      ret = 'RegExp(' + val + ')';
    } else if (val.nodeName) {
      // Different than PHP's DOMElement
      switch (val.nodeType) {
      case 1:
        if (typeof val.namespaceURI === 'undefined' || val.namespaceURI === 'http://www.w3.org/1999/xhtml') {
          // Undefined namespace could be plain XML, but namespaceURI not widely supported
          ret = 'HTMLElement("' + val.nodeName + '")';
        } else {
          ret = 'XML Element("' + val.nodeName + '")';
        }
        break;
      case 2:
        ret = 'ATTRIBUTE_NODE(' + val.nodeName + ')';
        break;
      case 3:
        ret = 'TEXT_NODE(' + val.nodeValue + ')';
        break;
      case 4:
        ret = 'CDATA_SECTION_NODE(' + val.nodeValue + ')';
        break;
      case 5:
        ret = 'ENTITY_REFERENCE_NODE';
        break;
      case 6:
        ret = 'ENTITY_NODE';
        break;
      case 7:
        ret = 'PROCESSING_INSTRUCTION_NODE(' + val.nodeName + ':' + val.nodeValue + ')';
        break;
      case 8:
        ret = 'COMMENT_NODE(' + val.nodeValue + ')';
        break;
      case 9:
        ret = 'DOCUMENT_NODE';
        break;
      case 10:
        ret = 'DOCUMENT_TYPE_NODE';
        break;
      case 11:
        ret = 'DOCUMENT_FRAGMENT_NODE';
        break;
      case 12:
        ret = 'NOTATION_NODE';
        break;
      }
    }
    return ret;
  };

  var _formatArray = function(obj, cur_depth, pad_val, pad_char) {
    var someProp = '';
    if (cur_depth > 0) {
      cur_depth++;
    }

    var base_pad = _repeat_char(pad_val * (cur_depth - 1), pad_char);
    var thick_pad = _repeat_char(pad_val * (cur_depth + 1), pad_char);
    var str = '';
    var val = '';

    if (typeof obj === 'object' && obj !== null) {
      if (obj.constructor && _getFuncName(obj.constructor) === 'PHPJS_Resource') {
        return obj.var_dump();
      }
      lgth = 0;
      for (someProp in obj) {
        lgth++;
      }
      str += 'array(' + lgth + ') {\n';
      for (var key in obj) {
        var objVal = obj[key];
        if (typeof objVal === 'object' && objVal !== null && !(objVal instanceof Date) && !(objVal instanceof RegExp) &&
          !
          objVal.nodeName) {
          str += thick_pad + '[' + key + '] =>\n' + thick_pad + _formatArray(objVal, cur_depth + 1, pad_val,
            pad_char);
        } else {
          val = _getInnerVal(objVal, thick_pad);
          str += thick_pad + '[' + key + '] =>\n' + thick_pad + val + '\n';
        }
      }
      str += base_pad + '}\n';
    } else {
      str = _getInnerVal(obj, thick_pad);
    }
    return str;
  };

  output = _formatArray(arguments[0], 0, pad_val, pad_char);
  for (i = 1; i < arguments.length; i++) {
    output += '\n' + _formatArray(arguments[i], 0, pad_val, pad_char);
  }

  this.echo(output);
}

print_r() in JavaScript

Here is the print_r() function:
http://phpjs.org/functions/print_r/
It depends on echo() too.

function print_r(array, return_val) {
  //  discuss at: http://phpjs.org/functions/print_r/
  // original by: Michael White (http://getsprink.com)
  // improved by: Ben Bryan
  // improved by: Brett Zamir (http://brett-zamir.me)
  // improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  //    input by: Brett Zamir (http://brett-zamir.me)
  //  depends on: echo
  //   example 1: print_r(1, true);
  //   returns 1: 1

  var output = '',
    pad_char = ' ',
    pad_val = 4,
    d = this.window.document,
    getFuncName = function(fn) {
      var name = (/\W*function\s+([\w\$]+)\s*\(/)
        .exec(fn);
      if (!name) {
        return '(Anonymous)';
      }
      return name[1];
    };
  repeat_char = function(len, pad_char) {
    var str = '';
    for (var i = 0; i < len; i++) {
      str += pad_char;
    }
    return str;
  };
  formatArray = function(obj, cur_depth, pad_val, pad_char) {
    if (cur_depth > 0) {
      cur_depth++;
    }

    var base_pad = repeat_char(pad_val * cur_depth, pad_char);
    var thick_pad = repeat_char(pad_val * (cur_depth + 1), pad_char);
    var str = '';

    if (typeof obj === 'object' && obj !== null && obj.constructor && getFuncName(obj.constructor) !==
      'PHPJS_Resource') {
      str += 'Array\n' + base_pad + '(\n';
      for (var key in obj) {
        if (Object.prototype.toString.call(obj[key]) === '[object Array]') {
          str += thick_pad + '[' + key + '] => ' + formatArray(obj[key], cur_depth + 1, pad_val, pad_char);
        } else {
          str += thick_pad + '[' + key + '] => ' + obj[key] + '\n';
        }
      }
      str += base_pad + ')\n';
    } else if (obj === null || obj === undefined) {
      str = '';
    } else {
      // for our "resource" class
      str = obj.toString();
    }

    return str;
  };

  output = formatArray(array, 0, pad_val, pad_char);

  if (return_val !== true) {
    if (d.body) {
      this.echo(output);
    } else {
      try {
        // We're in XUL, so appending as plain text won't work; trigger an error out of XUL
        d = XULDocument;
        this.echo('<pre xmlns="http://www.w3.org/1999/xhtml" style="white-space:pre;">' + output + '</pre>');
      } catch (e) {
        // Outputting as plain text may work in some plain XML
        this.echo(output);
      }
    }
    return true;
  }
  return output;
}

var_export() in JavaScript

You may also find the var_export() alternative useful, which also depends on echo():
http://phpjs.org/functions/var_export/

function var_export(mixed_expression, bool_return) {
  //  discuss at: http://phpjs.org/functions/var_export/
  // original by: Philip Peterson
  // improved by: johnrembo
  // improved by: Brett Zamir (http://brett-zamir.me)
  //    input by: Brian Tafoya (http://www.premasolutions.com/)
  //    input by: Hans Henrik (http://hanshenrik.tk/)
  // bugfixed by: Brett Zamir (http://brett-zamir.me)
  // bugfixed by: Brett Zamir (http://brett-zamir.me)
  //  depends on: echo
  //   example 1: var_export(null);
  //   returns 1: null
  //   example 2: var_export({0: 'Kevin', 1: 'van', 2: 'Zonneveld'}, true);
  //   returns 2: "array (\n  0 => 'Kevin',\n  1 => 'van',\n  2 => 'Zonneveld'\n)"
  //   example 3: data = 'Kevin';
  //   example 3: var_export(data, true);
  //   returns 3: "'Kevin'"

  var retstr = '',
    iret = '',
    value,
    cnt = 0,
    x = [],
    i = 0,
    funcParts = [],
    // We use the last argument (not part of PHP) to pass in
    // our indentation level
    idtLevel = arguments[2] || 2,
    innerIndent = '',
    outerIndent = '',
    getFuncName = function(fn) {
      var name = (/\W*function\s+([\w\$]+)\s*\(/)
        .exec(fn);
      if (!name) {
        return '(Anonymous)';
      }
      return name[1];
    };
  _makeIndent = function(idtLevel) {
    return (new Array(idtLevel + 1))
      .join(' ');
  };
  __getType = function(inp) {
    var i = 0,
      match, types, cons, type = typeof inp;
    if (type === 'object' && (inp && inp.constructor) &&
      getFuncName(inp.constructor) === 'PHPJS_Resource') {
      return 'resource';
    }
    if (type === 'function') {
      return 'function';
    }
    if (type === 'object' && !inp) {
      // Should this be just null?
      return 'null';
    }
    if (type === 'object') {
      if (!inp.constructor) {
        return 'object';
      }
      cons = inp.constructor.toString();
      match = cons.match(/(\w+)\(/);
      if (match) {
        cons = match[1].toLowerCase();
      }
      types = ['boolean', 'number', 'string', 'array'];
      for (i = 0; i < types.length; i++) {
        if (cons === types[i]) {
          type = types[i];
          break;
        }
      }
    }
    return type;
  };
  type = __getType(mixed_expression);

  if (type === null) {
    retstr = 'NULL';
  } else if (type === 'array' || type === 'object') {
    outerIndent = _makeIndent(idtLevel - 2);
    innerIndent = _makeIndent(idtLevel);
    for (i in mixed_expression) {
      value = this.var_export(mixed_expression[i], 1, idtLevel + 2);
      value = typeof value === 'string' ? value.replace(/</g, '&lt;')
        .
      replace(/>/g, '&gt;'): value;
      x[cnt++] = innerIndent + i + ' => ' +
        (__getType(mixed_expression[i]) === 'array' ?
          '\n' : '') + value;
    }
    iret = x.join(',\n');
    retstr = outerIndent + 'array (\n' + iret + '\n' + outerIndent + ')';
  } else if (type === 'function') {
    funcParts = mixed_expression.toString()
      .
    match(/function .*?\((.*?)\) \{([\s\S]*)\}/);

    // For lambda functions, var_export() outputs such as the following:
    // '\000lambda_1'. Since it will probably not be a common use to
    // expect this (unhelpful) form, we'll use another PHP-exportable
    // construct, create_function() (though dollar signs must be on the
    // variables in JavaScript); if using instead in JavaScript and you
    // are using the namespaced version, note that create_function() will
    // not be available as a global
    retstr = "create_function ('" + funcParts[1] + "', '" +
      funcParts[2].replace(new RegExp("'", 'g'), "\\'") + "')";
  } else if (type === 'resource') {
    // Resources treated as null for var_export
    retstr = 'NULL';
  } else {
    retstr = typeof mixed_expression !== 'string' ? mixed_expression :
      "'" + mixed_expression.replace(/(["'])/g, '\\$1')
      .
    replace(/\0/g, '\\0') + "'";
  }

  if (!bool_return) {
    this.echo(retstr);
    return null;
  }

  return retstr;
}

echo() in JavaScript

http://phpjs.org/functions/echo/

function echo() {
  //  discuss at: http://phpjs.org/functions/echo/
  // original by: Philip Peterson
  // improved by: echo is bad
  // improved by: Nate
  // improved by: Brett Zamir (http://brett-zamir.me)
  // improved by: Brett Zamir (http://brett-zamir.me)
  // improved by: Brett Zamir (http://brett-zamir.me)
  //  revised by: Der Simon (http://innerdom.sourceforge.net/)
  // bugfixed by: Eugene Bulkin (http://doubleaw.com/)
  // bugfixed by: Brett Zamir (http://brett-zamir.me)
  // bugfixed by: Brett Zamir (http://brett-zamir.me)
  // bugfixed by: EdorFaus
  //    input by: JB
  //        note: If browsers start to support DOM Level 3 Load and Save (parsing/serializing),
  //        note: we wouldn't need any such long code (even most of the code below). See
  //        note: link below for a cross-browser implementation in JavaScript. HTML5 might
  //        note: possibly support DOMParser, but that is not presently a standard.
  //        note: Although innerHTML is widely used and may become standard as of HTML5, it is also not ideal for
  //        note: use with a temporary holder before appending to the DOM (as is our last resort below),
  //        note: since it may not work in an XML context
  //        note: Using innerHTML to directly add to the BODY is very dangerous because it will
  //        note: break all pre-existing references to HTMLElements.
  //   example 1: echo('<div><p>abc</p><p>abc</p></div>');
  //   returns 1: undefined

  var isNode = typeof module !== 'undefined' && module.exports && typeof global !== "undefined" && {}.toString.call(
    global) == '[object global]';
  if (isNode) {
    var args = Array.prototype.slice.call(arguments);
    return console.log(args.join(' '));
  }

  var arg = '';
  var argc = arguments.length;
  var argv = arguments;
  var i = 0;
  var holder, win = this.window;
  var d = win.document;
  var ns_xhtml = 'http://www.w3.org/1999/xhtml';
  // If we're in a XUL context
  var ns_xul = 'http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul';

  var stringToDOM = function(str, parent, ns, container) {
    var extraNSs = '';
    if (ns === ns_xul) {
      extraNSs = ' xmlns:html="' + ns_xhtml + '"';
    }
    var stringContainer = '<' + container + ' xmlns="' + ns + '"' + extraNSs + '>' + str + '</' + container + '>';
    var dils = win.DOMImplementationLS;
    var dp = win.DOMParser;
    var ax = win.ActiveXObject;
    if (dils && dils.createLSInput && dils.createLSParser) {
      // Follows the DOM 3 Load and Save standard, but not
      // implemented in browsers at present; HTML5 is to standardize on innerHTML, but not for XML (though
      // possibly will also standardize with DOMParser); in the meantime, to ensure fullest browser support, could
      // attach http://svn2.assembla.com/svn/brettz9/DOMToString/DOM3.js (see http://svn2.assembla.com/svn/brettz9/DOMToString/DOM3.xhtml for a simple test file)
      var lsInput = dils.createLSInput();
      // If we're in XHTML, we'll try to allow the XHTML namespace to be available by default
      lsInput.stringData = stringContainer;
      // synchronous, no schema type
      var lsParser = dils.createLSParser(1, null);
      return lsParser.parse(lsInput)
        .firstChild;
    } else if (dp) {
      // If we're in XHTML, we'll try to allow the XHTML namespace to be available by default
      try {
        var fc = new dp()
          .parseFromString(stringContainer, 'text/xml');
        if (fc && fc.documentElement && fc.documentElement.localName !== 'parsererror' && fc.documentElement.namespaceURI !==
          'http://www.mozilla.org/newlayout/xml/parsererror.xml') {
          return fc.documentElement.firstChild;
        }
        // If there's a parsing error, we just continue on
      } catch (e) {
        // If there's a parsing error, we just continue on
      }
    } else if (ax) {
      // We don't bother with a holder in Explorer as it doesn't support namespaces
      var axo = new ax('MSXML2.DOMDocument');
      axo.loadXML(str);
      return axo.documentElement;
    }
    /*else if (win.XMLHttpRequest) {
     // Supposed to work in older Safari
      var req = new win.XMLHttpRequest;
      req.open('GET', 'data:application/xml;charset=utf-8,'+encodeURIComponent(str), false);
      if (req.overrideMimeType) {
        req.overrideMimeType('application/xml');
      }
      req.send(null);
      return req.responseXML;
    }*/
    // Document fragment did not work with innerHTML, so we create a temporary element holder
    // If we're in XHTML, we'll try to allow the XHTML namespace to be available by default
    //if (d.createElementNS && (d.contentType && d.contentType !== 'text/html')) {
    // Don't create namespaced elements if we're being served as HTML (currently only Mozilla supports this detection in true XHTML-supporting browsers, but Safari and Opera should work with the above DOMParser anyways, and IE doesn't support createElementNS anyways)
    if (d.createElementNS && // Browser supports the method
      (d.documentElement.namespaceURI || // We can use if the document is using a namespace
        d.documentElement.nodeName.toLowerCase() !== 'html' || // We know it's not HTML4 or less, if the tag is not HTML (even if the root namespace is null)
        (d.contentType && d.contentType !== 'text/html') // We know it's not regular HTML4 or less if this is Mozilla (only browser supporting the attribute) and the content type is something other than text/html; other HTML5 roots (like svg) still have a namespace
      )) {
      // Don't create namespaced elements if we're being served as HTML (currently only Mozilla supports this detection in true XHTML-supporting browsers, but Safari and Opera should work with the above DOMParser anyways, and IE doesn't support createElementNS anyways); last test is for the sake of being in a pure XML document
      holder = d.createElementNS(ns, container);
    } else {
      // Document fragment did not work with innerHTML
      holder = d.createElement(container);
    }
    holder.innerHTML = str;
    while (holder.firstChild) {
      parent.appendChild(holder.firstChild);
    }
    return false;
    // throw 'Your browser does not support DOM parsing as required by echo()';
  };

  var ieFix = function(node) {
    if (node.nodeType === 1) {
      var newNode = d.createElement(node.nodeName);
      var i, len;
      if (node.attributes && node.attributes.length > 0) {
        for (i = 0, len = node.attributes.length; i < len; i++) {
          newNode.setAttribute(node.attributes[i].nodeName, node.getAttribute(node.attributes[i].nodeName));
        }
      }
      if (node.childNodes && node.childNodes.length > 0) {
        for (i = 0, len = node.childNodes.length; i < len; i++) {
          newNode.appendChild(ieFix(node.childNodes[i]));
        }
      }
      return newNode;
    } else {
      return d.createTextNode(node.nodeValue);
    }
  };

  var replacer = function(s, m1, m2) {
    // We assume for now that embedded variables do not have dollar sign; to add a dollar sign, you currently must use {$$var} (We might change this, however.)
    // Doesn't cover all cases yet: see http://php.net/manual/en/language.types.string.php#language.types.string.syntax.double
    if (m1 !== '\\') {
      return m1 + eval(m2);
    } else {
      return s;
    }
  };

  this.php_js = this.php_js || {};
  var phpjs = this.php_js;
  var ini = phpjs.ini;
  var obs = phpjs.obs;
  for (i = 0; i < argc; i++) {
    arg = argv[i];
    if (ini && ini['phpjs.echo_embedded_vars']) {
      arg = arg.replace(/(.?)\{?\$(\w*?\}|\w*)/g, replacer);
    }

    if (!phpjs.flushing && obs && obs.length) {
      // If flushing we output, but otherwise presence of a buffer means caching output
      obs[obs.length - 1].buffer += arg;
      continue;
    }

    if (d.appendChild) {
      if (d.body) {
        if (win.navigator.appName === 'Microsoft Internet Explorer') {
          // We unfortunately cannot use feature detection, since this is an IE bug with cloneNode nodes being appended
          d.body.appendChild(stringToDOM(ieFix(arg)));
        } else {
          var unappendedLeft = stringToDOM(arg, d.body, ns_xhtml, 'div')
            .cloneNode(true); // We will not actually append the div tag (just using for providing XHTML namespace by default)
          if (unappendedLeft) {
            d.body.appendChild(unappendedLeft);
          }
        }
      } else {
        // We will not actually append the description tag (just using for providing XUL namespace by default)
        d.documentElement.appendChild(stringToDOM(arg, d.documentElement, ns_xul, 'description'));
      }
    } else if (d.write) {
      d.write(arg);
    } else {
      console.log(arg);
    }
  }
}

View more solutions

Comments

[Yusaf Khaliq]

no such thing but console.dir will do

[Vadzim]

Related: stackoverflow.com/questions/957537/…

[Adriana]

thanks, i use Firebug but i didn't know about this feature. also thanks for link.

[Adam F]

Nice. My firbug is glitchy so this works perfect.

[Admin]

console.log() also actual for google chrome without firebug.

[Chris Dixon]

Just remember (for other people reading this answer), if (for some reason) you're using IE6, see this to make console.log work: stackoverflow.com/questions/3326650/…

[fider]

JSON.stringify(object) usefull while have to check object in non-browser srcipts

[Kev]

I think this should be the accepted answer. The accepted answer depends on available tool of the running platform. While console.log is doing what the OP is looking for, it is certainly not the answer to the question. For example I'm using this code in Appcelerator Titanium, no console.log there.

[Jonline]

Really wish this answer had the up-votes; the addition of the JSON.stringify is a completely necessary addition!

[Nux]

Note that JSON.stringify(object) will not work for jQuery arrays of elements as it will not work for circular references. I've made a minor enhancement to Douglas Crockford JSON.decycle method so you can use it with DOM Nodes. Use console.log(JSON.stringify(JSON.decycle(object, true)) to dump almost any object. Fork: github.com/Eccenux/JSON-js/blob/master/cycle.js

[TorranceScott]

console.log has some issues with changing object/array/function values (I'm running into this with angular) but Amos has a function that outputs a string immediately and isn't affected by these problems: stackoverflow.com/a/11315561/1403755

[Maffelu]

+1 For the JSON.stringify(object). This is mainly a problem when Firebug is not available.

[JVE999]

I think this is nearly equivalent to finding a standard javascript function to do the same thing.

[Chris Rasys]

This really is not a proper answer as this is not an inherent feature or function of JavaScript and there are innumerable scenarios where one will absolutely not have access to console.log()

[Imperative]

Dang, that is a useful function.

[FuriousFolder]

@ChrisRasys "innumerable scenarios"? Would you one, please?

[Chris Rasys]

Numerous JS testing suites (New Relic Synthetics, Casper, Selenium). Generally, anything that runs in a self-contained environment typically negates access to the entire console (though some of them will pass through misc data).

[Simon Zyx]

a really nice addition to this answer would be using the built-in prettification of JSON.stringify like this: JSON.stringify(obj, null, 2) Works great in browsers and commandline. stackoverflow.com/a/7220510/3778409

[nerkn]

on tablet it is not working .

[brasofilo]

Totally nailed it, this is var_dump in JS.

[mike rodent]

Console.log is useful but not equivalent to print_r at all: you don't get a "pretty", neatly indented picture showing the structure of a complex object, such as a DOM node.

[mike rodent]

Very nice, but like Nux I wanted to do print_r for Node structures... I got hold of Nux's code but it didn't seem to work for me... just doing a really basic implementation instead.

[vladkras]

@FuriousFolder, any of millions of node.js apps especially deployed to server (though you can try to fins some server logs, your browser console will be empty)

[Ricardo Saracino]

this is the closest thing to var_dump

[akinuri]

+1 console.log(document.body) prints the element itself (HTML tree); console.dir(document.body), on the other hand, prints the element's properties.

[Brett]

console.log doesn't not give you the type of information var_dump does such as property type or length.

[FedeKrum]

S U P E R F U N C T I O N ! !

[Victor Paredes]

Woah this is a fantastic little tool. Thank you!