function checkEnter(btn, event)
{
    if (document.all)
    {
        if (event.keyCode == 13)
        {        
            var o = document.getElementById(btn);
            event.returnValue=false;
            event.cancel = true;
            o.click();
        }
    }
    else if (document.getElementById)
    {
        if (event.which == 13)
        {
            var o = document.getElementById(btn);
            event.returnValue=false;
            event.cancel = true;
            o.click();
        }
    }    
    else if (document.layers)
    {
        if(event.which == 13)
        {
            var o = document.getElementById(btn);
            event.returnValue=false;
            event.cancel = true;
            o.click();
        }
    }
}

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;
}