用JS做了一个简易的网页计算器
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>计算器</title> <script type="text/javascript"> window.onload = function () { var oInput01 = document.getElementById('input01'); var oInput02 = document.getElementById('input02'); var oFuhao = document.getElementById('fuhao'); var oBtn = document.getElementById('btn'); oBtn.onclick = function(){ var num01 = oInput01.value; var num02 = oInput02.value; var fuhao = oFuhao.value; //验证是否为空 if(num01==''||num02==''){ alert('输入框不能为空!'); return; } if(isNaN(num01)||isNaN(num02)){ alert('请输入数字!'); return; } switch (fuhao){ //这个value是字符串! case "0": alert((parseFloat(num01)*100+parseFloat(num02)*100)/100); break; case '1': alert((parseFloat(num01)*100-parseFloat(num02)*100)/100); break; case "2": alert(((parseFloat(num01)*100)*(parseFloat(num02)*100))/10000); break; case '3': alert(((parseFloat(num01)*100)/(parseFloat(num02)*100))); } } } </script> </head> <body> <h1>计算器</h1> <input type="text" name="" id="input01"> <select id="fuhao"> <option value="0">+</option> <option value="1">-</option> <option value="2">*</option> <option value="3">/</option> </select> <input type="text" name="" id="input02"> <input type="button" name="" value="计算" id="btn"> </body> </html>