js mengawal selang antara mengklik butang sekali lagi untuk mengelakkan kemahiran submission_javascript berulang

<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&#63;t=" + (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>

<div class="kv_item clear"> 
<span class="kv_label fl">验证码</span> 
<input name="checkCode" class="i_textshort fl" id="J_checkcode_input" onmousedown="ClearCodeMessage()" type="text" maxlength="6" autocomplete="off" onblur="CheckCode()" /> 
<img src="../../AjaxServer/CheckCodePic.ashx" height="28" id="vimg" alt="" style="float:left;margin:-1px 0 0 3px"/> 
<a id="J_refresh_checkcode" onclick="change()">看不清，换一张</a> 
<div class="msg msg-inline msg-weak hide" id="J_checkcode_tip"> 
<div class="msg-default msg-error"> 
<i class="msg-icon"></i> 
<div class="msg-content"> 
</div> 
</div> 
</div> 
</div>