1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2 <html> 3 4 <meta http-equiv="content-type" content="text/html; charset=UTF-8"> 5 6 <head> 7 8 <title>打折后价格计算</title> 9 10 <!-- 设置计算价格事件函数，取不同下拉打折数，计算结果送入文字框--> 11 12 <script type="text/javascript"> 13 14 function calculator(){ 15 var prices=document.getElementById("price"); 16 var discounts=document.getElementById("number"); 17 var pay; 18 var select=document.getElementById("payfunction"); 19 if((prices.value>=0&&!isNaN(prices.value))&&(discounts.value>=0&&!isNaN(discounts.value))&&prices.value!=""&&discounts.value!="") 20 { 21 pay=prices.value*discounts.value; 22 23 switch(parseInt(select.value)){ 24 case 1:pay=pay*0.5; break; 25 case 2:pay=pay*0.8; break; 26 case 3:pay=pay*0.6; break; 27 } 28 29 document.getElementById("result").value=pay; 30 alert("恭喜你，交易成功！"); 31 32 }else 33 { 34 prices.focus(); 35 prices.select(); 36 alert("请输入正确的价格和数量(也不能为空)！"); 37 } 38 39 } 40 41 42 </script> 43 44 45 </head> 46 47 <!-- 定义界面格式，设置下拉表，设置计算价格事件--> 48 49 <body> 50 <center> 51 <form name="discount" action="result.jsp" method="post"> 52 竞拍价格：<input type="text" id="price" style="width: 150px"/><br> 53 54 购买数量：<input type="text" id="number" style="width: 150px"/><br> 55 56 支付方式：<select id="payfunction" style="width: 150px"> 57 <option value="1">网银支付-打5折</option> 58 <option value="2">支付宝支付-打8折</option> 59 <option value="3" selected="true">Q币支付-打6折</option> 60 </select><br> 61 62 预计总价：<input type="text" id="result" style="width: 150px"><br> 63 64 <input type="button" id="allresult" value="计算总价" onclick="calculator()" /> 65 </form> 66 </center> 67 68 </body> 69 </html>
原文：http://www.cnblogs.com/lifescolor/p/3874116.html