js简单计算器和一个深坑
程序员文章站
2022-03-01 20:44:39
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今天用js写了一个简单的计算器,别的都还好说,遇到一个最大的坑应该是input输入的数字拿到之后竟然为string类型,type=”number”也不行!坑坑坑!!!
上代码:
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>计算器</title></head><body><input type="text" name="num1" id="num1" value=""><select name="ys" id="ys"><option value="+">+</option><option value="-">-</option><option value="*">*</option><option value="/">/</option><option value="%">%</option></select><input type="text" name="num2" id="num2" value=""><button onclick="js()">计算</button><p id="res"></p><script>function js() {var res = '',num1 = document.getElementById('num1').value,num2 = document.getElementById('num2').value,ysf = document.getElementById('ys').value,resObj = document.getElementById('res');console.log(num1);console.log(typeof (num1));if (num1.length < 1) {res += 'num1不能为空!';}if (num2.length < 1) {res += 'num2不能为空!'}num1 = parseFloat(num1);num2 = parseFloat(num2);if (isNaN(num1)) {res += 'num1不能为非数字!';}if (isNaN(num2)) {res += 'num2不能为非数字';}if (res.length == 0) {switch (ysf) {case '+':res = num1 + num2;break;case '-':res = num1 - num2;break;case '*':res = num1 * num2;break;case '/':if (num2 == 0) {res += '除数不能为零!';} else {res = num1 / num2;}break;case '%':if (num2 == 0) {res += '除数不能为零!';} else {res = num1 % num2;}break;}}resObj.innerText = res}</script></body></html>