<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
????var?result="";
????//獲取第一個(gè)輸入框的值
????var?x=document.getElementById("txt1").value;
????//獲取第二個(gè)輸入框的值
????var?y=document.getElementById("txt2").value;
????//獲取選擇框的值
???var?dd=document.getElementById("select").value;
????//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
????//設(shè)置結(jié)果輸入框的值?
????switch(dd){
????????case?"+":
????????????result?=??parseInt(x)+parseInt(y);
????????????break;
????????case?"-":
????????????result?=??parseInt(x)-parseInt(y);
????????????break;
????????case?"*":
????????????result?=??parseInt(x)*parseInt(y);
????????????break;
????????case?"/":
????????????result?=??parseInt(x)/parseInt(y);
????????????break;
????}
????//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(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>
2016-04-09
在 ? ??switch(dd){} 之前加上下面兩段便可以了：
? ? x= parseInt(x);
? ? y=parseInt(y);
2022-03-27
定義相同屬性的多個(gè)選擇器，中間用逗號(hào)隔開你的程序里沒(méi)有score[0],所以打印報(bào)錯(cuò)
2016-04-09
? ?document.getElementById("fruit").value?=result;
???}
???}
多了個(gè) ”? ?}“