var xmlHttp

function check_url(url)
{
	
	xmlHttp=GetXmlHttpObject()
	if (xmlHttp==null)
	  {
		  alert ("Browser does not support HTTP Request")
		  return
	  } 
	
	var webaddress = document.getElementById("webaddress").value 
	var url = "chk_url.php"
	
	url = url+"?webaddress="+webaddress	
	xmlHttp.onreadystatechange=stateChanged_url
	xmlHttp.open("GET",url,true)
	xmlHttp.send(null)
	} 
	
	function stateChanged_url() 
	{ 
		if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
		 { 
		
			 document.getElementById("url_available").innerHTML=xmlHttp.responseText 
		 } 
	}
	
	function GetXmlHttpObject()
	{
		var xmlHttp=null;
		try
		 {
			 // Firefox, Opera 8.0+, Safari
			 xmlHttp=new XMLHttpRequest();
		 }
		catch (e)
		 {
			 // Internet Explorer
			 try
			  {
				  xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
			  }
			 catch (e)
			  {
				  xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
			  }
		 }
		return xmlHttp;
}