这个代码没什么，贴上来，我想表达的重点隐藏在代码中，找找看！
<!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> <title>show date</title> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> name="mark"; function showLastDate() { alert(name); var reg=/^\d{4}\/\d{1,2}\/\d{1,2}$/; var inputdate=$("#indate").val(); if(!reg.test(inputdate)) { alert("please input date like:2013/1/14"); return; } var month=parseInt(inputdate.split("/")[1]); if(month>12||month==0) { alert("please input month range from 1-12"); return; } var showdate=getLastDate(inputdate); $("#lastdate").val(showdate); } function getLastDate(indate) { alert(name); var year=parseInt(indate.split("/")[0]); var month=parseInt(indate.split("/")[1]); //run nian var isrun=false; if((year%4==0 && year%100!=0)|| year%400==0) isrun=true; switch(month) { case 2: if(isrun) {return 29;} else {return 28;} case 1: case 3: case 5: case 7: case 8: case 10: case 12: return 31; default: return 30; } } </script> </head> <body style="margin-left:100px;margin-top:20px;"> <br><br> input date:<input id="indate" type="text" />example:2013/1/14<br><br> <input type="button" onclick="showLastDate()" value="Get Last Date"/><br><br> input date:<input id="lastdate" type="text" /><br> </body> </html>