var VisibleLabel = {
	input_class: 'populate',
	inputs_to_populate: [],
	init: function () {
		if (!document.getElementById) return;
		var inputs = document.getElementsByTagName('input');
		for (var i=0,len=inputs.length; i<len; i++) {
			if (inputs[i].className == this.input_class) this.inputs_to_populate.push(inputs[i]);
		}
		for (var i=0,len=this.inputs_to_populate.length; i<len; i++) {
			this.inputs_to_populate[i].onfocus = function () {
				VisibleLabel.previousSibling(this).style.zIndex = '-1';
			}
			this.inputs_to_populate[i].onblur = function () {
				if (this.value == '') {
					VisibleLabel.previousSibling(this).style.zIndex = '0';
				}
			}
		}
	},
	previousSibling: function (el) {
		label = el.previousSibling;
		while (label.nodeName != 'LABEL') {
			label = label.previousSibling;
		}
		return label;
	}
}

window.onload = function () {
	VisibleLabel.init();
}