<!DOCTYPE?html><html>?<head>??<title>?事件</title>????<script?type="text/javascript">???function?count(){????var?x,y,result,o;????x=document.getElementById("txt1").value;??????//獲取第一個輸入框的值????y=document.getElementById("txt2").value; //獲取第二個輸入框的值 o=document.getElementById("select").value; //獲取選擇框的值????switch(o){????????case?"+":????????????result=parseInt(x)+parseInt(y);????????????break;????????case?"-":????????????result=parseInt(x)-parseInt(y);????????????break;????????case?"*":????????????result=parseInt(x)*parseInt(y);????????????break;????????default:????????????result=parseInt(x)/parseInt(y);????}????document.getElementById("fruit")=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()"?/>????<input?type='text'?id='fruit'?/>????</body></html>
2019-03-07
document.getElementById("fruit")=result;這行代碼不對，應該是document.getElementById("fruit").value=result;