点击按钮先执行JS判断之后在进入后台代码

<asp:Button ID="btnTrue" runat="server" Text="保 存" 
OnClientClick="if(checkResult()){this.value='正在保存';this.disabled=true;}else {return false ;}" UseSubmitBehavior="false" class="btnblue1" onclick="btnTrue_Click" />




function checkResult() {
if ($("#txtTravelUserName").val() == "") {
alert("出差人姓名不能为空！");
$("#txtTravelUserName").focus();
return false;
}
else if ($.trim($("#txtTravelPost").val()) == "") {
alert("职务不能为空！");
$("#txtTravelPost").focus();
return false;
}
return true;
}