loadingImage = new Image(85,24); 
loadingImage.src="/images/loading-button.gif"; 
function validateUpload(form){
	// Trim whitespace
	for(var x = 0; x < form.elements.length; x++) {
		if(form.elements[x].type == 'text' || form.elements[x].type == 'hidden') {
	    	form.elements[x].value = Trim(form.elements[x].value);
		}
	}
	// userfile
	str = form.userfile.value;
	str = str.toLowerCase()
	if (isWhitespace(str)) {
		alert('Please select a picture to upload.');
		form.userfile.focus();
		return false;
	}
	// check if image is remote image from URL
	function isUrl(s) {
		var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/
		return regexp.test(s);
	}
	if (isUrl(str)){
		alert("Remote file upload not supported. Please select a file from your computer.");
		form.userfile.focus();
		form.userfile.select();
		return false;
	}
	// make sure file is a supported image type
	var fileExtensionRegxp 	= /^.+\.((jpg)|(gif)|(jpeg)|(png))$/;
	if (fileExtensionRegxp.test(str) != true){
		alert("Invalid file format. Only JPG, GIF, and PNG files are supported.");
		form.userfile.focus();
		form.userfile.select();
		return false;
	}
	// change button to loading image
	document.getElementById("uploadSubmit").src = loadingImage.src;
	// submit form
	return true;
}