请教一个(获取系统时间)的问题
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>计时事件做的 表</title><script type="text/javascript">function startTime(){var today=new Date()var h=today.getHours()var m=today.getMinutes()var s=today.getSeconds()// add a zero in front of numbers<10m=checkTime(m)s=checkTime(s)document.getElementById('txt').innerHTML=h+":"+m+":"+st=setTimeout('startTime()',500)}//这里不明白checkTime()函数是怎么运行的function checkTime(i){if (i<10) {i="0" + i} return i}</script></head><body><body onload="startTime()"><div id="txt"></div></body></body></html>