// test a URL for validity
function testURL (url) {
	if (!url || url == 'http://') {
		alert("You must provide a valid URL before you can preview it.");
		return;
	}

	if (url.match(/^https?:\/\//i)) {
		var win = window.open(url);
		if (win == null) alert("Unable to open a new browser window,\n This might be due to a 'popup blocker'");
	} else {
		alert("Please provide a valid URL beginning with http://");
	}
}