html

<input class="getCode" type="button" value="获取验证码"/>

css

.getCode{
	position: absolute;
	right: 0px;
	top: 0px;
	display: block;
	width: 110px;
	height: 38px;
	line-height: 36px;
	color: #333;
	letter-spacing: 0px;
	border: 1px solid #E0E0E0;
	border-radius: 4px;
	text-align: center;
	cursor: pointer;
	margin: 0;
	padding: 0;
}
.getCode.dis{
	opacity: 0.6;
	cursor: pointer;
	background: #eee;
}

js

//例数计时
    //t = 例数时间，obj = 按钮class或id
    function timing(t,obj){
        if(t>0){
            var t = t-1;
            $(obj).attr('disabled','disabled').addClass('dis');
            $(obj).val('重新获取('+t+')');
            setTimeout(function(){
                timing(t,obj);
            },1000);
        }else{
            $(obj).removeAttr('disabled').removeClass('dis');
            $(obj).val('重新获取');
        }
    }

调用

timing(60,'.getCode');