JS 时间与时间戳的相互转换

<script type="text/javascript">
    
    var time = "2015-04-22 21:41:43";//2015-4-22 21:41:43
    var temp = time.split(' ');
    var arr = temp[0].split('-');
    var brr = temp[1].split(':');
    var timestamp = new Date(Date.UTC(arr[0],arr[1]-1,arr[2],+brr[0]-8,brr[1],brr[2]));
    var timestamp = timestamp.getTime()/1000;
    alert(timestamp);
    

    function getDate(tm){
        var tt=new Date(parseInt(tm) * 1000).toLocaleString().replace(/年|月/g, "-").replace(/日/g, " ")
        return tt;
    }
    alert(getDate('1429711045'));
    </script>