<!DOCTYPE?html>
<html>
?<head>?
??<title>?事件</title>????
??<script?type="text/javascript">??
???function?count(){??
?????var?one=document.getElementById("txt1").value;????
?????var?two=document.getElementById("txt2").value;
?????var?a=doucument.getElementById("select").value;
?????var?num;
?????switch(a){ ????
?????case?"+": ????????
?????????????num=parseInt(one)+parseInt(two); ??
?????????????break; ??
?????case?"-":
?????????????num=parseInt(one)-parseInt(two); ???
?????????????break; ???
?????case?"*": ?????
?????????????num=parseInt(one)*parseInt(two);
?????????????break; ???
?????case?"/"?: ?????
?????????????num=parseInt(one)/parseInt(two); ??
?????????????break;
????????????}
???????document.getElementById("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></html>
2020-02-27
var?a=doucument.getElementById("select").value;?這一行的document,多寫了個u。第9行