<script type="text/javascript" language="javascript"> var wait = 60; function change() { $o = $("#J_refresh_checkcode"); if(wait == 0) { $o.removeAttr("disabled"); $o.html("看不清？换一张"); wait = 60; } else { $o.attr("disabled", true); $o.attr("font-color", "gray"); $o.html(wait + "秒后可重新获取"); wait--; if(wait == 59) { var imgNode = document.getElementById("vimg"); imgNode.src = "../../AjaxServer/CheckCodePic.ashx" + (new Date()).valueOf(); // 这里加个时间的参数是为了防止浏览器缓存的问题 $("#J_checkcode_tip").addClass("hide"); $("#J_checkcode_tip>div").html(""); $("#<%=hidPicMessage.ClientID%>").val(""); } setTimeout(function() { change() }, 1000) } }</script>

则 html如下：

<div> <span>验证码</span> <input name="checkCode" id="J_checkcode_input" onmousedown="ClearCodeMessage()" type="text" maxlength="6" autocomplete="off" onblur="CheckCode()" /> <img src="../../AjaxServer/CheckCodePic.ashx" height="28" id="vimg" alt=""/> <a id="J_refresh_checkcode">看不清，换一张</a> <div id="J_checkcode_tip"> <div> <i></i> <div> </div> </div> </div> </div>