The general principle is to set the calculation price event function, take different drop-down discount numbers, and send the calculation results into the text box. Interested friends can refer to the following
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <head> <title>打折后价格计算</title> <!-- 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--> <script type="text/javascript"> function calculator(){ var prices=document.getElementById("price"); var discounts=document.getElementById("number"); var pay; var select=document.getElementById("payfunction"); if((prices.value>=0&&!isNaN(prices.value))&&(discounts.value>=0&&!isNaN(discounts.value))&&prices.value!=""&&discounts.value!="") { pay=prices.value*discounts.value; switch(parseInt(select.value)){ case 1:pay=pay*0.5; break; case 2:pay=pay*0.8; break; case 3:pay=pay*0.6; break; } document.getElementById("result").value=pay; alert("恭喜你,交易成功!"); }else { prices.focus(); prices.select(); alert("请输入正确的价格和数量(也不能为空)!"); } } </script> </head> <!-- 定义界面格式,设置下拉表,设置计算价格事件--> <body> <center> <form name="discount" action="result.jsp" method="post"> 竞拍价格:<input type="text" id="price" style="width: 150px"/> 购买数量:<input type="text" id="number" style="width: 150px"/> 支付方式:<select id="payfunction" style="width: 150px"> <option value="1">网银支付-打5折</option> <option value="2">支付宝支付-打8折</option> <option value="3" selected="true">Q币支付-打6折</option> </select> 预计总价:<input type="text" id="result" style="width: 150px"> <input type="button" id="allresult" value="计算总价" onclick="calculator()" /> </form> </center> </body> </html>
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