我们研究一下ASP.NET的js代码(下载页面中WebResource.axd?d=SD1NUwMQGhYXe3jLq5kyhRg80avbG6v4rFgfT8pf7Lg1&t=633409665581718750指向的文件）发现用来显示错误消息的是ValidatorUpdateDisplay这个函数来完成的，关键的一句，是 val.style.visibility = val.isvalid ? "hidden" : "visible"; 如果我们想用alert方式显示的话，只需将这句改成alert(val.innerHTML)就可以了，但我们想做得更好看一点，做成类似于QQ聊天窗口的效果，效果可看下图：
要实现这个效果，需要以下几个图片。
 |
 |
 |
 |
 |
 |
以下是源码：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="myvalid.aspx.cs" Inherits="Test.myvalid" %>
<html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>无标题页</title><style>
.MsgC
{
border-top:solid 1px #C6C3C6; height:6px; background-color:#FFFBEF; font-size:1px;
}.MsgL{ BACKGROUND: url(images/vMsgL.gif) no-repeat left top; width:7px; height:6px; }.MsgR{ BACKGROUND: url(images/vMsgR.gif) no-repeat ; width:24px; height:6px;}.MsgBL{ BACKGROUND: url(images/vMsgBL.gif) no-repeat left top; width:7px; height:6px; }.MsgBC{ BACKGROUND: url(images/vMsgBC.gif) repeat-x; height:19px; }.MsgBR{ BACKGROUND: url(images/vMsgBR.gif) no-repeat left top; width:24px; height:19px; }
</style></head><body style="font-size:12px"> <form id="form1" runat="server"> <div style="font-weight:bold;height:60px"> 打造自己的验证控件：</div> 姓名：<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" Display="dynamic" ControlToValidate="TextBox1" ErrorMessage="请输入姓名！" SetFocusOnError="True"></asp:RequiredFieldValidator><br /> 证件号：<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox> <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" Display="dynamic" ControlToValidate="TextBox2" ErrorMessage="请输入证件号!" SetFocusOnError="True"></asp:RequiredFieldValidator> <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" Display="dynamic" ControlToValidate="TextBox2" ErrorMessage="证件号格式不符！" ValidationExpression="d{17}[d|X]|d{15}"></asp:RegularExpressionValidator><br /> <asp:Button ID="Button1" runat="server" Text="确定" /> </form></body></html><script type="text/javascript"> function ValidatorUpdateDisplay(val) { if (typeof(val.display) == "string") { if (val.display == "None") { return; } if (val.display == "Dynamic") { //val.style.display = val.isvalid ? "none" : "inline"; // return; } } if ((navigator.userAgent.indexOf("Mac") > -1) && (navigator.userAgent.indexOf("MSIE") > -1)) { val.style.display = "inline"; } ShowZfValidMsg(val); // val.style.visibility = val.isvalid ? "hidden" : "visible";}function Page_ClientValidate(validationGroup) { Page_InvalidControlToBeFocused = null; if (typeof(Page_Validators) == "undefined") { return true; } var i; for (i = 0; i < Page_Validators.length; i++) { ValidatorValidate(Page_Validators[i], validationGroup, null); //Added By zhaofeng if(!Page_Validators[i].isvalid)// only show one errmsg { Page_IsValid = false; Page_BlockSubmit = !Page_IsValid; return false; } //Added End } ValidatorUpdateIsValid(); ValidationSummaryOnSubmit(validationGroup); Page_BlockSubmit = !Page_IsValid; return Page_IsValid;}function ShowZfValidMsg(val){ //window.status = val.isvalid; var tbId = "tbValidMsg";//+val.controltovalidate; var tb = document.getElementById(tbId); if(val.isvalid && tb == null) return; if(tb == null) { tb = document.createElement("table"); tb.border= 0 ; tb.id = tbId; tb.cellSpacing = 0 ; tb.cellPadding = 0 ; var tr = tb.insertRow(0); var cell = tr.insertCell(0); cell.className = "MsgL"; cell = tr.insertCell(1); cell.className = "MsgC"; cell.innerHTML = " "; cell = tr.insertCell(2); cell.className = "MsgR"; //the second row tr = tb.insertRow(1); cell = tr.insertCell(0); cell.bgColor = "#FFFBEF"; cell.style.cssText= "border-left:solid 1px #C6C3C6"; cell.innerHTML = " " cell = tr.insertCell(1); cell.bgColor = "#FFFBEF"; cell.height = 40; cell.innerHTML = "<div style='float:left;padding-top:1px'><img src='images/yellowalert.gif' /></div>"+ "<span style='color:black;font-size:12px;height:40px;100px;padding-top:10px;padding-bottom:10px;padding-right:0px;padding-left:3px'></span>"; cell = tr.insertCell(2); cell.bgColor = "#FFFBEF"; cell.style.cssText= "border-right:solid 1px #C6C3C6"; cell.innerHTML = " " //the third row tr = tb.insertRow(2); cell = tr.insertCell(0); cell.className = "MsgBL"; cell = tr.insertCell(1); cell.innerHTML = " "; cell.className = "MsgBC"; cell = tr.insertCell(2); cell.className = "MsgBR"; document.body.appendChild(tb); tb.style.cssText= "position:absolute;zIndex:500"; } tb.rows[1].cells[1].childNodes[1].innerHTML = val.innerHTML; tb.style.display = val.isvalid?"none":""; var obj = document.getElementById(val.controltovalidate); if(obj !=null) { var ary = GetElePos(obj); var l = ary[0]+obj.offsetWidth-tb.offsetWidth; if(l<0) l= 0 ; var t = ary[1]-tb.offsetHeight+15; if(t<0) t = 0 ; tb.style.left = l tb.style.top = t; } return ; } function GetElePos(e) { var t=e.offsetTop; var l=e.offsetLeft; while(e=e.offsetParent){ t+=e.offsetTop; l+=e.offsetLeft; } return [l, t]; }</script>如果想在整个系统中应用这个效果的话，只需将页面尾部的javascript脚本封装到一个js文件中，放在需要应用的页面的尾部，无需再添加任何代码。
