jQuery.css(): Firefox don't return 'auto' values

Question

I\'m setting top or bottom and left or right values to a few elements. When i\'m trying to access this values with Firefox (16.0.2), i get a wrong value for top

Answer 1

Just remove the position style and you will get auto instead of computed value.

div {
    top: auto;
    bottom:20px;    
    right:20px;
    left:0px;
}

you can test it here.

Answer 2

You Can Get integer Value of top when you set 'auto' with below code:

$(function(){
    var top = $('div').offset().top;
    alert(top);
});​

• offset Return Position Value When you Set To Auto

Answer 3

This is down to the browser and how it interprets the styles, it is somewhat out of your control. However, with particular CSS and jQuery workarounds you should be able to get around it. For instance, if you do not need to the item to be positioned absolutely then you could remove this, or change it to position:static;

Have a look at this question.

As to why Chrome and IE return different values: .css() provides a unified gateway to the browsers' computed style functions, but it doesn't unify the way the browsers actually compute the style. It's not uncommon for browsers to decide such edge cases differently.

Answer 4

I also had this annoying problem.

Some browsers return the computed position if the element is visible at the moment. The trick is to hide it, read the css and then make it visible again (if was not already hidden).

I wrote a convenient function that takes care of this and will return auto in Firefox.

jsFiddle

var getCss = function($elem, prop) {
        var wasVisible = $elem.css('display') !== 'none';
        try {
            return $elem.hide().css(prop);
        } finally {
            if (wasVisible) $elem.show();
        }
    };


alert( getCss($('div'), 'top') );

The finally is just to bring visibility back to the element, just before the function returns.

You should use this function only for situations where you expect auto to be returned.