JS实现加减乘除四则运算器
2017-10-15 19:55
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<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var txt1Value = document.getElementById("txt1").value;
var txt2Value = document.getElementById("txt2").value;
var operator = document.getElementById("select").value;
var result;
switch(operator){
case "+":result = Number(txt1Value) + Number(txt2Value);
break;
case "-":result = Number(txt1Value) - Number(txt2Value);
break;
case "*":result = Number(txt1Value) * Number(txt2Value);
break;
case "/":result = Number(txt1Value) / Number(txt2Value);
break;
}
document.getElementById("fruit").value = result;
}
</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>
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