function get_Code() {
 var Dv_CodeFile = "Dv_GetCode.asp";
 if(document.getElementById("imgid"))
  document.getElementById("imgid").innerHTML = '<img src=http://www.cngf.net/newcngf/bbs/'+Dv_CodeFile+'?t='+Math.random()+'" alt="点击刷新验证码" style="cursor:pointer;border:0;vertical-align:middle;" onclick="this.src=\''+Dv_CodeFile+'?t=\'+Math.random()" />'
}