<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
???????
????//獲取第一個輸入框的值
????var?num1=document.getElementById("txt1").value;
//獲取第二個輸入框的值
var?mum2=document.getElementById("txt2").value;
//獲取選擇框的值
var?opt=document.getElementById("select").value;
//獲取通過下拉框來選擇的值來改變加減乘除的運算法則
var?result=""
switch(opt){
???case?"+":
???????result?=?parseFloat(num1)+parseFloat(num2);
???????break;
???case?"-":
???????result?=?parseFloat(num1)-parseFloat(num2);
???????break;
???case?"*":
???????result?=parseFloat(num1)*parseFloat(num2);
???????break;
???case?"/":
???????result?=?parseFloat(num1)/parseFloat(num2);
}
????//設(shè)置結(jié)果輸入框的值?
????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()"/>?<!--通過?=?按鈕來調(diào)用創(chuàng)建的函數(shù)，得到結(jié)果-->?
???<input?type='text'?id='fruit'?/>???
?</body>
</html>
為什么點按鈕后面結(jié)果出不來
春泥遇上花
2017-02-25 16:59:37
