Left() function in Javascript or jQuery

var stuff = $('#block').css("left")

1008px

parseInt(stuff);

String.prototype.left = function(n) {
    return this.substring(0, n);
}

var num = "1008px".left(4);

var value = "1080px";
var num = value.replace(/[^d]+/g, '');
// or
var num = value.replace(/D+/g, '');
// or
var num = value.match(/d+/)[0];