Javascript进阶篇6-11的编程练习
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>JS进阶篇编程练习</title>
<script type = "text/Javascript">
function count(){
//获取第一个输入框的值,parseInt防止获取的为字符串
var txt1 = parseInt(document.getElementById("txt1").value);
//获取第二个输入框的值
var txt2 = parseInt(document.getElementById("txt1").value);
//获取选择框的值
var txt3 = document.getElementById("select").value;
//获取通过下拉框来选择的值来改变加减乘除运算
switch(tet3){
case "+":sum = txt1 + txt2; break;
case "-":sum = txt1 - txt2; break;
case "*":sum = txt1 * txt2; break;
case "/":sum = txt1 / txt2; break;
}
//设置输入框的值
getElementById("friut").value = sum;
}
</script>
</head>
<body>
<input type="text" id="txt1"/>
<select id="select">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input type="text" id="txt2"/>
<input type="button" value="=" onclick = "count()"/> <!--通过 = 按钮来调用创建的函数，得到结果-->
<input type="text" id="fruit"/>
</body>
</html>运行完点击=没结果啊？怎么回事呢？亲们
