jquery -Get CSS properties values for a not yet applied class

Question

i have a same question asked here(wasnt able to comment on it,maybe dont have a priviledge) , i want to get css width value defined in stylesheet but not yet applied on any element in dom ,(its bootstrap css with grid with responsive media queries)

 .span6 {
 width: 570px;
 }

However solution provided in above referenced question return 0 i.e like this

$('<div/>').addClass('span6').width();

but works if i do something like this

 $('<div/>').addClass('span6').hide().appendTo('body').width();

any easy way without appending that div?

Solution 1

In order to read a CSS property value from a nonexistent element, you need to dynamically insert that element (as hidden) to the DOM, read the property and finally remove it:

var getCSS = function (prop, fromClass) {

    var $inspector = $("<div>").css('display', 'none').addClass(fromClass);
    $("body").append($inspector); // add to DOM, in order to read the CSS property
    try {
        return $inspector.css(prop);
    } finally {
        $inspector.remove(); // and remove from DOM
    }
};

jsFiddle here

Solution 2

Great answer by Jose. I modified it to help with more complex css selectors.

var getCSS2 = function (prop, fromClass, $sibling) {

    var $inspector = $("<div>").css('display', 'none').addClass(fromClass);
    if($sibling != null){
        $sibling.after($inspector); //append after sibling in order to have exact 
    } else {
        $("body").append($inspector); // add to DOM, in order to read the CSS property
    }
    try {
        return $inspector.css(prop);
    } finally {
        $inspector.remove(); // and remove from DOM
    }
};

JSFiddle

Comments

[Fabrício Matté]

That's basically what OP is doing - .css('display', 'none') is virtually the same as .hide(), but +1 for expanding it to an usable function and the finally block which runs 'after' a return.

[Jaideep Singh]

may be thats the only easy way to do it with "write less and do more jquery" :P

[Alex Filipovici]

I've tried it for background-position, but it's returning 0% 0% instead of the actual value...

[Jose Rui Santos]

@AlexFilipovici You should be doing something wrong. You can see here that works fine. jsfiddle.net/cVfFc/1