<!DOCTYPE html><html> <head> <title> 事件</title> <script type="text/javascript"> function count(){ var a=document.getElementById("txt1").value; var b=document.getElementById("txt2").value; var c=document.getElementById("select").value; var result=""; switch(c) { case "+": result = parseFloat(a) + parseFloat(b); break; case "-": result = parseFloat(a) - parseFloat(b); break; case "*": result = parseFloat(a) * parseFloat(b); break; default: result = parseFloat(a) / parseFloat(b); } document.getElementById("fruit").value = 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()"/> <!--通过 = 按钮来调用创建的函数，得到结果--> <input type='text' id='fruit' /> </body></html>
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<script type="text/javascript">
function count(){
var a=document.getElementById("txt1").value;
var b=document.getElementById("txt2").value;
var c=document.getElementById("select").value;
var result="";
switch(c)
{
case "+":
result = parseFloat(a) + parseFloat(b);
break;
case "-":
result = parseFloat(a) - parseFloat(b);
break;
case "*":
result = parseFloat(a) * parseFloat(b);
break;
default:
result = parseFloat(a) / parseFloat(b);
}
document.getElementById("fruit").value = result;
}
</script>只是函数最后少了个 }
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