<input type="button" id="btn" value="免费获取验证码" />

<script type="text/javascript">
var wait=60;
function time(o) {
        if (wait == 0) {
            o.removeAttribute("disabled");           
            o.value="免费获取验证码";
            wait = 60;
        } else {
            o.setAttribute("disabled", true);
            o.value="重新发送(" + wait + ")";
            wait--;
            setTimeout(function() {
                time(o)
            },
            1000)
        }
    }
document.getElementById("btn").onclick=function(){time(this);}
</script>

<input type="button" id="btn" value="免费获取验证码" onclick="settime(this)" />
<script type="text/javascript">
var countdown=60;
function settime(val) {
if (countdown == 0) {
val.removeAttribute("disabled");
val.value="免费获取验证码";
countdown = 60;
} else {
val.setAttribute("disabled", true);
val.value="重新发送(" + countdown + ")";
countdown--;
}
setTimeout(function() {
settime(val)
},1000)
}
</script>

<script>
i=9
function change()
{
i--;
p.value="同意"+i
if(i==0)
{ p.disabled=false}
else
setTimeout("change()",1000)
}
window.onload=change;
</script>
<input type=button name=p disabled></font>
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