问表单和ajax脚本混用

EN

function refresh(){
        var ajaxRequest;

        try{
            // Opera 8.0+, Firefox, Safari
            ajaxRequest = new XMLHttpRequest();
        } catch (e){
            // Internet Explorer Browsers
            try{
                ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try{
                    ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e){
                    // Something went wrong
                    alert("Your browser broke!");
                    return false;
                }
            }
        }
        ajaxRequest.onreadystatechange = function(){
            if(ajaxRequest.readyState == 4){
                document.getElementById("Chats").innerHTML= ajaxRequest.responseText;
            }
        }
        ajaxRequest.open("POST", "chatAjax.php", true);
        ajaxRequest.send(null);
        setTimeout("refresh()",10000);
    }