Adding extra zeros in front of a number using jQuery?

Question

I have file that are uploaded which are formatted like so

MR 1

MR 2

MR 100

MR 200

MR 300

Answer 1

This is the function that I generally use in my code to prepend zeros to a number or string.

The inputs are the string or number (str), and the desired length of the output (len).

var PrependZeros = function (str, len) {
    if(typeof str === 'number' || Number(str)){
    str = str.toString();
    return (len - str.length > 0) ? new Array(len + 1 - str.length).join('0') + str: str;
}
else{
    for(var i = 0,spl = str.split(' '); i < spl.length; spl[i] = (Number(spl[i])&& spl[i].length < len)?PrependZeros(spl[i],len):spl[i],str = (i == spl.length -1)?spl.join(' '):str,i++);
    return str;
}

};

Examples:

PrependZeros('MR 3',3);    // MR 003
PrependZeros('MR 23',3);   // MR 023
PrependZeros('MR 123',3);  // MR 123
PrependZeros('foo bar 23',3);  // foo bar 023

Answer 2

Just for a laugh do it the long nasty way....:
(NOTE: ive not used this, and i would not advise using this.!)

function pad(str, new_length) {
    ('00000000000000000000000000000000000000000000000000' + str).
    substr((50 + str.toString().length) - new_length, new_length)
}