javascript eval 的一個例子

<script>
var the_unevaled_answer = "2 + 3";
var the_evaled_answer = eval("2 + 3");
alert("the un-evaled answer is " + the_unevaled_answer + " and the evaled answer is " + the_evaled_answer);
</script>

 

eval會求出表達式內的值來。

如果換成2+3+a,則不執行。