<body>
<input type="text" name="num1" id="num1">
<input type="radio" name="radio1" value="radio1" checked="checked">
+
<input type="radio" name="radio1" value="radio2">
-
<input type="text" name="num2" id="num2">
=
<input type="text" name="num3" id="num3">
<input type="button" name="button1" id="button2" value="运算"
onclick="operation()">
</body>
<input type="text" name="num1" id="num1">
<input type="radio" name="radio1" value="radio1" checked="checked">
+
<input type="radio" name="radio1" value="radio2">
-
<input type="text" name="num2" id="num2">
=
<input type="text" name="num3" id="num3">
<input type="button" name="button1" id="button2" value="运算"
onclick="operation()">
</body>
文本显示后如下图
+ - =
点运算后显示如下图
+ - =
<script type="text/javascript">
function operation() {
function operation() {
//获取填入表单的数值并转化成浮点数值；
var num1 = parseFloat(document.getElementById("num1").value);
var num2 = parseFloat(document.getElementById("num2").value);
var num1 = parseFloat(document.getElementById("num1").value);
var num2 = parseFloat(document.getElementById("num2").value);
//获取num3的Id
var num3 = document.getElementById("num3");
var num3 = document.getElementById("num3");
//获取单选按钮的组的Id
var radio = document.getElementsByName("radio1");
var commend;
var radio = document.getElementsByName("radio1");
var commend;
//遍历单选按钮判断哪个按钮被选中
for ( var i = 0; i < radio.length; i++) {
if (radio[i].checked == true) {
commend = radio[i].value;
break;
}
}
for ( var i = 0; i < radio.length; i++) {
if (radio[i].checked == true) {
commend = radio[i].value;
break;
}
}
//判断填入的内容是否为数字
if (num1 != null && num2 != null) {
if (isNaN(num1) || isNaN(num2)) {
if (isNaN(num1)) {
alert("第一个输入框输入的不是数字或者没有输入数值");
} else {
alert("第二个输入框输入的不是数字或者没有输入数值");
}
if (num1 != null && num2 != null) {
if (isNaN(num1) || isNaN(num2)) {
if (isNaN(num1)) {
alert("第一个输入框输入的不是数字或者没有输入数值");
} else {
alert("第二个输入框输入的不是数字或者没有输入数值");
}
//判断选中的单选框的属性，
} else if (commend == "radio1") {
var num4 = num1 + num2;
num3.value = num4;
} else if (commend == "radio2") {
var num4 = num1 - num2;
num3.value = num4;
}
}
}
</script>
} else if (commend == "radio1") {
var num4 = num1 + num2;
num3.value = num4;
} else if (commend == "radio2") {
var num4 = num1 - num2;
num3.value = num4;
}
}
}
</script>