按钮防止多次点击

防止按钮在短时间内多次点击，多次触发事件

<button bindtap="toGetWithdraw" >确定</button>
    //点击确定按键
    toGetWithdraw:function(){
        var that=this;
        if(that.data.showis==true){//按钮是否可以点击
                that.zhifu();
                that.setData({
                    showis:false
                })
                setTimeout(function(){
                    that.setData({
                        showis:true
                    })
                },4000)
        }
    },