誰能告訴我這個簡易計算器錯哪了，onclick的時候沒反應呢
?<script type="text/javascript">
?? function count(){
????? var num="";
????? var t1= document.getElementById("txt1").value;
????? var t2= document.getElementById("txt2").value;
????? var sel=document.getElementById("select").value;
????? switch(sel){
??????? case "+": num = parseInt(t1) + parseInt(t2); break;
?????? ?
??????? case "-": num = parseInt(t1) - parseInt(t2); break;
??????? case "*": num = parseInt(t1) * parseInt(t2); break;
??????? default : num = parseInt(t1) / parseInt(t2); break;
????? }
????? document.setElementById("fruit").value = num;
? }
? </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 = 按鈕來調用創建的函數，得到結果-->
?? <input type='text' id='fruit' />? ?
?</body>
2016-07-20
document.setElementById("fruit").value = num;修改為document.getElementById("fruit").value = num;
2016-07-22
?document.setElementById("fruit").value?=?num;//?setElementById?錯誤?應該是getElementById2016-07-20
<script type="text/javascript">
?? function count(){
????? var num = 0 ;
????? var t1= document.getElementById("txt1").value;
????? var t2= document.getElementById("txt2").value;
????? var sel=document.getElementById("select").value;
//??? document.write(t1+" "+t2+ " " + sel);
????? switch(sel){
??????? case "+": num = parseInt(t1) + parseInt(t2); break;
?????? ?
??????? case "-": num = parseInt(t1) - parseInt(t2); break;
??????? case "*": num = parseInt(t1) * parseInt(t2); break;
??????? default : num = parseInt(t1) / parseInt(t2); break;
????? }
????? //document.write(num);
????? document.getElementById("fruit").innerText = num ;
? }
? </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 = 按鈕來調用創建的函數，得到結果-->
?? <input type='text' id='fruit' />? ?
?</body>
2016-07-20
應該是document.getElementById("fruit").value=num;不是document.setElementById("fruit").value=num;
2016-07-20
? document.setElementById("fruit").value = num; ?這里應該是document.getElementById("fruit").value = num;
2016-07-20
你比我牛逼 我不會