点击发送验证码会有一个60秒的倒计时，用js实现
<script>
$("#lnkChange").click(function(){
SysSecond =60;
var InterValObj;
InterValObj=self.setInterval("setRemainTime()",1000)
});
function setRemainTime() {
if (SysSecond > 0) {
SysSecond = SysSecond - 1;
$("#lnkChange").attr('href', 'javascript:void(0)');
$("#lnkChange").attr('disabled', 'disabled');
$("#lnkChange").html( '还剩' + SysSecond + '秒');
} else {
window.clearInterval(InterValObj);
$("#lnkChange").attr('href', 'javascript:getCode()');
$("#lnkChange").removeAttr('disabled');
$("#lnkChange").html('再次发送');
}
}
</script>
