<body>
<h3>简易计算器</h3>
<form>
<input type="text" size ="5",id="num1" value=""/>
<select id="operator">
<option value="+" selected="selected">+</option>
<option value="-" >-</option>
<option value="*" >*</option>
<option value="/">/</option>
</select>
<input type="text" size="5" id="num2" value=""/>
<input type="button" value="=" id="ok"/>
<input type="text" size="16" id="result" readonly="true">
</form>
</body>
<script>
var oNum1=document.getElementById("num1");
var oNum2=document.getElementById("num2");
var oOper=document.getElementById("operator");
var oOk=document.getElementById("ok");
var res ="";
oOk.onclick=function(){
var num1=parseFloat(oNum1.value);
var num2=parseFloat(oNum2.value);
var oper=oOper.value;
if (num1 && num2){
switch(oper){
case "+":res =num1+num2; break;
case "-":res =num1-num2; break;
case "*":res =num1*num2; break;
case "/" :res =num1/num2; break;
}
}else{
res ="请输入不为0的数值";
}
document.getElementById('result').value=res;
}
</script>
错误显示
