如何让TreeView不回发

var foo = null;
        function getNode(evt) {
            evt1 = window.event ? window.event.srcElement : evt.target;
            if (evt1.tagName && evt1.tagName != "INPUT") {
                if (evt1.tagName == "IMG") {
                    return true;
                }
                else {
                    //接下来的 3 行代码用于控制选中的节点的颜色。
                    if (foo) foo.style.color = "black"; //最初的颜色
                    evt1.style.color = "red"; //当前选中的节点的颜色
                    foo = evt1; //保存当前节点

                    var imgPlus = null;
                    var sb = evt1.previousSibling;
                    if (sb && sb.tagName == "INPUT") { //处理显示复选框节点的情况
                        imgPlus = document.getElementById(sb.id.replace(/CheckBox/gi, ""));
                    }
                    else if (evt1.tagName == "A") { //处理无复选框节点的情况
                        if (!/^javascript\:__doPostBack\(/gi.test(evt1.href)) {
                            return true;
                        }
                        imgPlus = document.getElementById(evt1.id.replace(/^(.+)t(\d+)$/gi, "$1n$2"));
                    }
                    if (imgPlus) {
                        eval(imgPlus.href)
                    }
                    if (window.event) {
                        window.event.returnValue = false;
                        return false;
                    }
                    else {
                        evt.preventDefault();
                        evt.stopPropagation();
                    }
                }
            }
        }

 

protected void Page_Load(object sender, EventArgs e)
    {
        TreeView1.Attributes.Add("onclick", "getNode(event);");
    }