function get_http(){   
    var xmlhttp;   
    /*@cc_on  
    @if (@_jscript_version >= 5)  
        try {  
            xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");  
        } catch (e) {  
            try {  
                xmlhttp = new   
                ActiveXObject("Microsoft.XMLHTTP");  
            } catch (E) {  
                xmlhttp = false;  
            }  
        }  
    @else  
        xmlhttp = false;  
    @end @*/   
    if (!xmlhttp && typeof XMLHttpRequest != 'undefined') {   
        try {   
            xmlhttp = new XMLHttpRequest();   
        } catch (e) {   
            xmlhttp = false;   
        }   
    }   
    return xmlhttp;   
}