function createXmlHttpRequest()
{
	var $http_request = null;
	if(window.XMLHttpRequest) { 
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType('text/xml');
		}
	}
	else if (window.ActiveXObject) { 
		try {
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
			http_request = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {}
		}
	}
	if (!http_request) { 
		return false;
	}
	return http_request;
}
function CheckEmail(value){
	var objRegExp = /^[a-zA-Z]([a-zA-Z0-9]*[-_.]?[a-zA-Z0-9]+)+@([\w-]+\.)+[a-zA-Z]{2,}$/
	if(value==""){
		alert("Email address cannot be empty");
		return false; 
	}else if(!objRegExp.test(value)) {
		alert("Email address format error");
		return false; 
	}else{
		return true;
	}
}

function startSearch(){
	var  keywords = document.getElementById("keywords").value;
	if(!keywords){
		alert('Please input the keywords.');
		return;
	}
	document.products_search.submit();
}

function subscribe(type){
	var  email_address = document.getElementById("email_address").value;
	if(!CheckEmail(email_address)){
		return;
	}
	if(!email_address){
		alert('Please input your email address.');
		return;
	}
	var url = "./includes/subscribe.php?action="+type+"&email_address=" + email_address;
	url += "&temp="+Math.random();
	var xmlHttp = createXmlHttpRequest();
	xmlHttp.onreadystatechange = function(){
		if (xmlHttp.readyState == 4) {
			if (xmlHttp.status == 200) {
				alert(xmlHttp.responseText);
				document.getElementById("email_address").value = "";
			}
		}
	}
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
}