<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
???????
????var?a1=document.getElementById("txt1").value;//獲取第一個(gè)輸入框的值
var?a2=document.getElementById("txt2").value;//獲取第二個(gè)輸入框的值
var?b1=document.getElementById("select").value;//獲取選擇框的值
var?result;
switch(b1)
{
????case?"+"
????result=parseFloat(a1)+parseFloat(a2);
????break;
????
????case?"-"
????result=parseFloat(a1)-parseFloat(a2);
????break;
????
????case?"/"
????result=parseFloat(a1)/parseFloat(a2);
????break;
????
????case?"*"?
????result=parseFloat(a1)*parseFloat(a2);
????break;
????
}//獲取通過(guò)下拉框來(lái)選擇的值來(lái)改變加減乘除的運(yùn)算法則
????document.getElementById("fruit").value=result;//設(shè)置結(jié)果輸入框的值?
????
???}
??</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(guò)?=?按鈕來(lái)調(diào)用創(chuàng)建的函數(shù)，得到結(jié)果-->?
???<input?type='text'?id='fruit'?/>???
?</body>
</html>
2017-08-18
case 語(yǔ)句結(jié)束時(shí)少了 “:” 號(hào)，導(dǎo)致瀏覽器編譯報(bào)錯(cuò)，程序無(wú)法運(yùn)行。