String method to convert to and from a data attribute

toAndFromDataAttribute.js

String.prototype.toDataProp = function() {
	var min = "A".charCodeAt(0),
		max = "Z".charCodeAt(0),
		res = "data-";
	this.split("").forEach(function(char, i) {
		var cc = char.charCodeAt(0);
		if (cc >= min && cc <= max) {
			res += ((i > 0) ? "-" : "") + String.fromCharCode(cc + 32);
		} else {
			res += char;
		}
	});
	return res;
}

String.prototype.fromDataProp = function() {
	var min = "A".charCodeAt(0),
		max = "Z".charCodeAt(0),
		res = "",
		temp = this.split('data-')[1];
	temp.split("-").forEach(function(word, i) {
		if (i > 0) {
			res += String.fromCharCode(word.charCodeAt(0) - 32) + word.substr(1, word.length - 1);
		} else {
			res += word;
		}
	});
	return res;
}