关于JS倒计时

<script type="text/javascript" language="javascript">         function CurrTime() {             var count = 30;             var str = "";             if (count * 60 != 0) {                 var temp = count / 60 + "";                 temp = temp.split(".");                 str = "0" + temp[0] + ":" + ((count % 60 - 1) > 9 ? count % 60 - 1 + "" : "0" + (count % 60 - 1)) + ":" + "59";             } else {                 str = "0" + ((count / 60 > 1) ? (count / 60 - 1) : 0) + ":" + 59 + ":" + "59";             }             document.getElementByIdx_x("currTime").innerHTML = str;             setTimeout(uceOneSec, 1000);         }         function uceOneSec() {             var currTime = document.getElementByIdx_x("currTime");             var tempTime = currTime.innerHTML.split(":");             var hour = tempTime[0];             var minute = tempTime[1];             var second = tempTime[2];             if (second >= 1) {                 second = (second - 1 > 9) ? (second - 1) : "0" + (second - 1);