var matrixRegex = /matrix((-?d*.?d+),s*0,s*0,s*(-?d*.?d+),s*0,s*0)/,
    matches = $(element).css('-webkit-transform').match(matrixRegex);

var element = document.querySelector('...');
var scaleX = element.getBoundingClientRect().width / element.offsetWidth;

node = $("#yourid")[0];
var curTransform = new WebKitCSSMatrix(window.getComputedStyle(node).webkitTransform);
alert(curTransform.a); // curTransform is an object,
alert(curTransform.d); // a through f represent all values of the transformation matrix

function getTransformValue(element,property){
        var values = element[0].style.webkitTransform.split(")");
        for (var key in values){
            var val = values[key];
            var prop = val.split("(");
            if (prop[0].trim() == property)
                return prop[1];
        }
        return false;
    }

// returns matrix(1,0,0,1,0,0)
var matrix = window.getComputedStyle(element).transform;
var matrixArray = matrix.replace("matrix(", "").matrix.split(",");
var scaleX = parseFloat(matrixArray[0]);
var scaleY = parseFloat(matrixArray[3]);
// bonus round - gets translate values
var translateX = parseFloat(matrixArray[4]);
var translateY = parseFloat(matrixArray[5]); // parseFloat ignores ")"