How to Call a JS function using OnClick event

javascript html forms validation html-validation

445,304

Solution 1

You are attempting to attach an event listener function before the element is loaded. Place fun() inside an onload event listener function. Call f1() within this function, as the onclick attribute will be ignored.

function f1() {
    alert("f1 called");
    //form validation that recalls the page showing with supplied inputs.    
}
window.onload = function() {
    document.getElementById("Save").onclick = function fun() {
        alert("hello");
        f1();
        //validation code to see State field is mandatory.  
    }
}

JSFiddle

Solution 2

You could use addEventListener to add as many listeners as you want.

  document.getElementById("Save").addEventListener('click',function ()
    {
     alert("hello");
     //validation code to see State field is mandatory.  
    }  );

Also add script tag after the element to make sure Save element is loaded at the time when script runs

Rather than moving script tag you could call it when dom is loaded. Then you should place your code inside the

document.addEventListener('DOMContentLoaded', function() {
    document.getElementById("Save").addEventListener('click',function ()
    {
     alert("hello");
     //validation code to see State field is mandatory.  
    }  ); 
});

example

Solution 3

I removed your document.getElementById("Save").onclick = before your functions, because it's an event already being called on your button. I also had to call the two functions separately by the onclick event.

     <!DOCTYPE html>
      <html>
      <head>
      <script>
       function fun()
        {
         alert("hello");
         //validation code to see State field is mandatory.  
        }   
        function f1()
        {
          alert("f1 called");
           //form validation that recalls the page showing with supplied inputs.    
        }
      </script>
      </head>
      <body>
      <form name="form1" id="form1" method="post">
                State: 
                <select id="state ID">
                   <option></option>
                   <option value="ap">ap</option>
                   <option value="bp">bp</option>
                </select>
       </form>

       <table><tr><td id="Save" onclick="f1(); fun();">click</td></tr></table>

   </body>
   </html>

Solution 4

Using the onclick attribute or applying a function to your JS onclick properties will erase your onclick initialization in <head>.

What you need to do is add click events on your button. To do that you’ll need the addEventListener or attachEvent (IE) method.

<!DOCTYPE html>
<html>
<head>
    <script>
        function addEvent(obj, event, func) {
            if (obj.addEventListener) {
                obj.addEventListener(event, func, false);
                return true;
            } else if (obj.attachEvent) {
                obj.attachEvent('on' + event, func);
            } else {
                var f = obj['on' + event];
                obj['on' + event] = typeof f === 'function' ? function() {
                    f();
                    func();
                } : func
            }
        }

        function f1()
        {
            alert("f1 called");
            //form validation that recalls the page showing with supplied inputs.    
        }
    </script>
</head>
<body>
    <form name="form1" id="form1" method="post">
        State: <select id="state ID">
        <option></option>
        <option value="ap">ap</option>
        <option value="bp">bp</option>
        </select>
    </form>

    <table><tr><td id="Save" onclick="f1()">click</td></tr></table>

    <script>
        addEvent(document.getElementById('Save'), 'click', function() {
            alert('hello');
        });
    </script>
</body>
</html>

Solution 5

You can also do this with an anonymous javascript function by using a iife. Please note that this is considered a bad practice, though there are those rare times when there is no other option.

...
<span onclick="(function() { // function code here })())">click me!</span>
...

View more solutions

445,304

Author by

Vineeth Varma

Updated on July 13, 2022

Comments

Vineeth Varma almost 2 years

I am trying to call my JS function that I added in the header. Please find below code that shows my problem scenario. Note: I don't have access to the body in my application. Everytime I click on the element with id="Save" it only calls f1() but not fun(). How can I make it call even my fun()? Please help.

  <!DOCTYPE html>
  <html>
  <head>

  <script>

   document.getElementById("Save").onclick = function fun()
    {
     alert("hello");
     //validation code to see State field is mandatory.  
    }   

    function f1()
    {
       alert("f1 called");
       //form validation that recalls the page showing with supplied inputs.    
    }

  </script>
  </head>
  <body>
  <form name="form1" id="form1" method="post">
            State: 
            <select id="state ID">
               <option></option>
               <option value="ap">ap</option>
               <option value="bp">bp</option>
            </select>
   </form>

   <table><tr><td id="Save" onclick="f1()">click</td></tr></table>

   </body>
   </html>