Question

I was trying to write a function which takes the Id of an element and gives the list of all the style attributes(with their values) applied on that element. It should consider the inline style as well as the style defined in css file.

I could get the function work when I provide style attribute name along with the id of the element in parameter but I just want to pass the id of the element and should be able to get all the style attributes along with values.

function should be something like getStyleById(elementId);

PFB the code snippet so far:

var styleNode = [];
var styles;
var sty = x.style;
    
var len = sty.length;
    
for (var i = 0; i < len; i++) 
{
    styles = sty.item(i);
       
    if (x.currentStyle)     //IE for External/Global Styles
    {
        var a = x.currentStyle[styles];
            
        styleNode.push(styles + ":" + a);
    }
    else if (document.defaultView && document.defaultView.getComputedStyle)    //Firefox,Chrome,Safari for External/Global Styles
    {
        var b = document.defaultView.getComputedStyle(x, "").getPropertyValue(styles);
          
        styleNode.push(styles + ":" + b);
    }
    else           //Works in Inline Styles only
    {
        var c = x.style[styles];
          
        styleNode.push(styles + ":" + c);
    }
}

Answer 1

Use the following method:

• Loop through the indexes of the CSSStyleDeclaration object (getComputedStyle) to get each known property name. Use getPropertyValue + this name to get the value.
  Code optimalization: Do not use getComputedStyle for each iteration, but store it in a variable outside the loop.
• Use an ordinary for ( name in object ) loop for currentStyle.
• Use the same looping method for inline styles

Code:

function getStyleById(id) {
    return getAllStyles(document.getElementById(id));
}
function getAllStyles(elem) {
    if (!elem) return []; // Element does not exist, empty list.
    var win = document.defaultView || window, style, styleNode = [];
    if (win.getComputedStyle) { /* Modern browsers */
        style = win.getComputedStyle(elem, '');
        for (var i=0; i<style.length; i++) {
            styleNode.push( style[i] + ':' + style.getPropertyValue(style[i]) );
            //               ^name ^           ^ value ^
        }
    } else if (elem.currentStyle) { /* IE */
        style = elem.currentStyle;
        for (var name in style) {
            styleNode.push( name + ':' + style[name] );
        }
    } else { /* Ancient browser..*/
        style = elem.style;
        for (var i=0; i<style.length; i++) {
            styleNode.push( style[i] + ':' + style[style[i]] );
        }
    }
    return styleNode;
}