abstract：<html><head><meta charset="UTF-8"><title>導(dǎo)航欄</title><script type="text/javascript">function jsq(op) {var a = parseFloat(document.getElementById(
<html>
<head>
<meta charset="UTF-8">
<title>導(dǎo)航欄</title>
<script type="text/javascript">
function jsq(op) {
var a = parseFloat(document.getElementById("num1").value);
var b = parseFloat(document.getElementById("num2").value);
switch (op) {
case "+":
document.getElementById("ans").value = a + b;
break;
case "-":
document.getElementById("ans").value = a - b;
break;
case "*":
document.getElementById("ans").value = a * b;
break;
case "/":
if (b == 0) {
alert("除數(shù)不能為0");
} else {
document.getElementById("ans").value = a / b;
}
break；
case "%":
if (b == 0) {
alert("除數(shù)不能為0");
} else {
document.getElementById("ans").value = a%b;
}
}
}
</script>
<body>
第一個(gè)數(shù):
<input type="text" id="num1">
<br> 第二個(gè)數(shù)字:
<input type="text" id="num2">
選擇運(yùn)算：
<input type="button" value="+" onClick="jsq('+')">
<input type="button" value="-" onClick="jsq('-')">
<input type="button" value="*" onClick="jsq('*')">
<input type="button" value="/" onClick="jsq('/')">
<input type="button" value="%" onClick="jsq('%')">
<br> 答案:
<input type="text" id="ans">
</body>
</head>
</html>
演示地址 -> http://47.107.64.136/JS/1/
Correcting teacher：天蓬老師Correction time：2019-01-13 09:16:27
Teacher's summary：如果在:document.getElementById("num1").value, 外面套一個(gè): trim(document.getElementById("num1").value)會(huì)更好, 以防止用戶不小心多敲了空格, 例如,如果輸入: 35 , 這樣就可以把前后的空格過(guò)濾掉了