帮忙看看js正则表达式中怎样限制以下两个字符

Question

<script language=javascript>
var re=/^([A-E0-9]|(F(?!(F)))){2}$/i
var str="FF"
alert(re.test(str))
</script>

Answer 1

wrong, use this:<script type="text/javascript">
<!--
function wr(){
    for(var i=0,j=arguments.length;i<j;i++)
        document.write(arguments[i],"&nbsp;&nbsp;&nbsp;");
    document.write("<br>");
}var reg = /^(([0-9a-e][0-9a-f])|(f[0-9a-e]))$/gi;var ar = ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"];for(var i=0;i<ar.length;i++)
    for(var j=0;j<ar.length;j++){
        var reg = /^(([0-9a-e][0-9a-f])|(f[0-9a-e]))$/gi;
        wr(ar[i]+ar[j]," : ",reg.test(ar[i]+ar[j]));
    }
var reg = /^(([0-9a-e][0-9a-f])|(f[0-9a-e]))$/gi;
var str = "123";
wr(str," : ",reg.test(str));var reg = /^(([0-9a-e][0-9a-f])|(f[0-9a-e]))$/gi;
var str = "1";
wr(str," : ",reg.test(str));var reg = /^(([0-9a-e][0-9a-f])|(f[0-9a-e]))$/gi;
var str = "FFF";
wr(str," : ",reg.test(str));var reg = /^(([0-9a-e][0-9a-f])|(f[0-9a-e]))$/gi;
var str = "f";
wr(str," : ",reg.test(str));//-->
</script>

Answer 2

zhaoxiaoyang(梅雪香@深圳) 很奇怪
为什么你的代码在FF下是true false交替的结果呢?
我用的是FF 2.0

Answer 3

原因是加了g，正则这里加了G下次就是从结尾开始。所以是false

Answer 4

http://community.csdn.net/Expert/TopicView3.asp?id=5422907这里面详细写了