不会出现乱码的ajax 方法

var proxy = null;
        function create() {
            if (window.ActiveXObject) {
                try
                {
                    proxy = new ActiveXObject("MSXML2.XMLHTTP");
                }
                catch(e)
                {
                    proxy = new ActiveXObject("Microsoft.XMLHTTP");
                }
            }
            else
            {
                proxy = new XMLHttpRequest();
            }
        }
        function executeMethod()
        {
            create();
            var str = escape(document.getElementById("txtContent").value);
            var params = "cmd=ajax&name=" + document.getElementById("txtContent").value;
            proxy.open("post", "Ajax.aspx", true);
            proxy.onreadystatechange = readyMethod;
            proxy.setRequestHeader("Content-type","application/x-www-form-urlencoded");
            proxy.send(params);
        }
        function readyMethod() {
            if (proxy.readyState == 1) {
                document.getElementById("btnAjax").value = "已发送";
            }
            else
            {
                if(proxy.readyState==4&&proxy.status==200) {
                
                    alert(proxy.responseText);
                    document.getElementById("btnAjax").value = "发送成功";
                }
            }
            
        }