<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script>
function count(){
var oTxt1=document.getElemnetById("txt1").value;
var oTxt2=document.getElemnetById("txt2").value;
var oSlt=document.getElemnetById("select").value;
var result="";
switch(oSlt)
{
case "+":
result=parseFloat(oTxt1)+parseFloat(oTxt2);
break;
case "-":
result=parseFloat(oTxt1)-parseFloat(oTxt2);
break;
case "*":
result=parseFloat(oTxt1)*parseFloat(oTxt2);
break;
default:
result=parseFloat(oTxt1)/parseFloat(oTxt2);
}
document.getElemnetById("fruit").value=result;
}
</script>
</head>
<body>
<input type="text" id="txt1">
<select name="" 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>getElementById拼错了，不是getElemnetById