dedecms自定义表单加入验证码

<input name="validate" type="text" id="vdcode" style="text-transform:uppercase;" size="8"/>
 
<img id="vdimgck" align="absmiddle" onClick="this.src=this.src+'?'" style="cursor: pointer;" alt="看不清？点击更换" src="../include/vdimgck.php"/>
 
<a href=”javascript:vide(-1);” onClick=”changeAuthCode();”>看不清？ </a>

<script type="text/javascript" language="javascript"> 
function changeAuthCode() 
{ var num = new Date().getTime(); 
var rand = Math.round(Math.random() * 10000);
num = num + rand; 
$('#ver_code').css('visibility','visible'); 
if ($("#vdimgck")[0]) { $("#vdimgck")[0].src = "../include/vdimgck.php?tag=" + num; } 
return false; 
}</script>

$validate = empty($validate) ? '' : strtolower(trim($validate));
 
$svali = strtolower(GetCkVdValue()); 
 
if(($validate=='' || $validate != $svali) && preg_match("/6/",$safe_gdopen))
 
{ResetVdValue();
 
ShowMsg('验证码不正确!',-1,0,1000);
 
exit();}