padLeft function

function padLeft(width, char) {
 var pad = '';
 for (var i = 0; i < width; i++) {
 pad += char;
 }
 return pad;
}
var str = '1100';
var pad = padLeft(8, '0');
var paddedString = pad.substring(0, pad.length - str.length) + str;
console.log(paddedString); //This will print on the console -> '00001100'