js倒計時60s

.btn {
    width:120px;
    height:40px;   
    float:left;
    color: white;
    background-color: #3498db;
    border-radius: 6px;
    text-align: center;
    text-decoration: none;

}

<input type="button"  class="btn" value="獲取驗證碼"  οnclick="clickButton(this)" />

function clickButton(obj){

    var obj = $(obj);
    obj.attr("disabled","disabled");
    var time = 60;
    var set=setInterval(function(){
    obj.val(--time+"(s)");
    }, 1000);

    setTimeout(function(){
    obj.attr("disabled",false).val("重新獲取驗證碼");
    clearInterval(set);
    }, 60000);
}