js获取当前时间 年月日分秒，不足自动补0

 var nowYear=new Date().getFullYear().toString()
 var nowMonth=(new Date().getMonth() + 1).toString()
 var nowDay=new Date().getDate().toString();
 var nowHours= new Date().getHours().toString();       //获取当前小时数(0-23)
 var nowMin= new Date().getMinutes().toString();     //获取当前分钟数(0-59)
 var nowSeconds= new Date().getSeconds().toString();     //获取当前秒数(0-59)
function timeAdd0(str) {
    if(str.length<=1){
        str='0'+str;
    }
    return str
}
 nowYear=timeAdd0(nowYear)
 nowMonth=timeAdd0(nowMonth)
 nowDay=timeAdd0(nowDay)
 nowHours=timeAdd0(nowHours)
 nowMin=timeAdd0(nowMin)
 nowSeconds=timeAdd0(nowSeconds)
 alert(nowYear+nowMonth+nowDay+nowHours+ nowMin+nowSeconds)