<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>無標題頁</title>
<link href="../../css/style.css" rel="stylesheet" type="text/css" />
<script language="javascript">
function ChangeValidCode()
{
document.getElementById("IMG1").src='../../Components/ValiadCode1.aspx';
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table width="267" border="0" align="center" cellpadding="0" cellspacing="2" bgcolor="#FFFFFF" height="145">
<tr>
<td style="width: 69px"><div align="right">用戶名: </div></td>
<td>
<input id="tbUserCode" type="text" runat="server" maxlength="36" class="inputBlur" onblur="this.className='inputBlur'" onfocus="this.className='inputFocus'" style="width:140px; height:17px;"/>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="*"
ControlToValidate="tbUserCode"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td style="width: 69px"><div align="right">密 碼: </div></td>
<td><input id="tbUserPwd" type="password" runat="server" maxlength="10" class="inputBlur" onblur="this.className='inputBlur'" onfocus="this.className='inputFocus'" style="width:140px; height:17px;"/>
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ErrorMessage="*" ControlToValidate="tbUserPwd"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td style="width: 69px"><div align="right">驗證碼: </div></td>
<td><input id="tbValidCode" type="text" maxlength="4" runat="server" class="inputBlur" onblur="this.className='inputBlur'" onfocus="this.className='inputFocus'" style="width:43px; height:17px;"/>
<img src="../../Components/ValiadCode1.aspx" name="IMG1" border="0" align="middle" id="IMG1" runat="server" /> <a href="javascript:ChangeValidCode();" title="看不清?點擊更換顯示驗證碼">看不清？</a>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="*" ControlToValidate="tbValidCode"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td colspan="2" align="center" height="33">
<input id="ibtnLogin" type="submit" runat="server" value="登 錄" onserverclick="ibtnLogin_ServerClick" class="btn_L1" onMouseOver="this.className='btn_L2'" onMouseOut="this.className='btn_L1'"/>
<input id="Button1" type="reset" runat="server" value="取 消" class="btn_L1" onMouseOver="this.className='btn_L2'" onMouseOut="this.className='btn_L1'" />
</td>
</tr>
<tr id="trError">
<td colspan="2" align="center">
<asp:Label ID="lblCodeError" runat="server" Text="驗證碼錯誤！" ForeColor="red" Visible="false"></asp:Label>
<asp:Label ID="lblPwdError" runat="server" Text="用戶名或密碼錯誤！" ForeColor="red" Visible="false"></asp:Label></td>
</tr>
</table>
</div>
</form>
</body>
</html>
在點擊“看不清”切換驗證碼時，驗證碼卻不變化。
查找資料原來是頁面緩存引起的。
解決辦法：在url後邊在加上一段話來改變提交時間。
例如 ：
var newUrl = "原url"+"&timeStamp="+new Date().getTime();
例如 ：
var newUrl = "原url"+"&timeStamp="+new Date().getTime();
或者
在IE設置中"檢查所有網頁的較新版本"構選"每次訪問網頁時檢查"即可以達到目的了