/**
 * Copy the value of an input field's title attribute to its value attribute.
 * Clear the input field on focus if its value is the same as its title.
 * Repopulate the input field on blur if it is empty.
 * Hide the input field's associated label if it has one.
 */
var autoPopulate = {
	sInputClass:'inputMail', // Class name for input elements to autopopulate
	sHiddenClass:'structural', // Class name that gets assigned to hidden label elements
	bHideLabels:true, // If true, labels are hidden
	/**
	 * Main function
	 */
	init:function() {
		// Check for DOM support
		if (!document.getElementById || !document.createTextNode) {return;}
		// Find all input elements with the given className
		var arrInputs = common.getElementsByClassName(document, 'input', autoPopulate.sInputClass);
		var iInputs = arrInputs.length;
		var oInput;
		for (var i=0; i<iInputs; i++) {
			oInput = arrInputs[i];
			// Make sure it's a text input
			if (oInput.type != 'text') { continue; }
			// Hide the input's label
			if (autoPopulate.bHideLabels) { autoPopulate.hideLabel(oInput.id); }
			// If value is empty and title is not, assign title to value
			if ((oInput.value == '') && (oInput.title != '')) { oInput.value = oInput.title; }
			// Add event handlers for focus and blur
			common.addEvent(oInput, 'focus', function() {
				// If value and title are equal on focus, clear value
				if (this.value == this.title) {
					this.value = '';
					this.select(); // Make input caret visible in IE
				}
			});
			common.addEvent(oInput, 'blur', function() {
				// If the field is empty on blur, assign title to value
				if (!this.value.length) { this.value = this.title; }
			});
		}
	},
	hideLabel:function(sId) {
		var arrLabels = document.getElementsByTagName('label');
		var iLabels = arrLabels.length;
		var oLabel;
		for (var i=0; i<iLabels; i++) {
			oLabel = arrLabels[i];
			if (oLabel.htmlFor == sId) {
				oLabel.className = oLabel.className + ' ' + autoPopulate.sHiddenClass;
			}
		}
	}
};

/**
 * Init on window load.
 * Replace this with a call to your own addEvent/DOMReady function if you use one.
 */
common.addEvent(window, 'load', autoPopulate.init);