1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 2 <html xmlns="http://www.w3.org/1999/xhtml"> 3 <head> 4 <title></title> 5 <style type="text/css"> 6 *{margin:0px;padding:0px;} 7 body{font-size:12px;} 8 9 .box{margin:10px;padding:10px;} 10 .box h3{margin:10px 0px;border-bottom:1px solid red;padding-bottom:10px;} 11 .box p{line-height:20px;} 12 13 #excelbox{width:800px;border-collapse:collapse;margin:20px;} 14 #excelbox tr{height:30px;} 15 #excelbox tr td{border:1px solid #aaccff;} 16 #excelbox tr td.focus{border:1px solid red;} 17 #excelbox tr td input{border:none;width:99%;height:30px;line-height:30px;} 18 </style> 19 <script type="text/javascript"> 20 21 function add(){ 22 var sum=0; 23 for(var i=1;i<=100;i++){ 24 if(i%3==0){ 25 sum+=i; 26 } 27 } 28 alert(sum); 29 } 30 </script> 31 </head> 32 <body> 33 <div class="box"> 34 <h3>试题要求</h3> 35 <p> 36 1.使用javascript计算100以内，能够被3整除的数字之和。<br /> 37 <input type="button" value="点击一下，获取100以内能够被3整除的数字之和" onclick="add()" /> 38 </p> 39 </div> 40 </body> 41 </html>
原文：http://www.cnblogs.com/mr-guan/p/5043751.html