javascript正则表达式不起作用
[英]javascript regex doesn't work
问题描述
I want to create a register form. 
我想创建一个注册表单。 Naturally, every user have to choose a username and a password, but I want to, that there are only small az characters and numbers 0-9 in the usernames. 当然，每个用户都必须选择用户名和密码，但我想，用户名中只有小的az字符和数字0-9。 I want to use regex and javascript. 我想使用正则表达式和JavaScript。 Here is the code: 这是代码：
<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
function check(value) {
valid_qwe = /[a-z0-9\-]$/;
trying = valid_qwe.test(value);
alert("The name: " + value + "\nBe allowed: " + trying);
return valid_qwe;
}
</script>
</head>
<body>
<input type="text" autofocus id="qwe" name="qwe" value="" />
<input type="submit" onClick="check(document.getElementById('qwe').value);" value="Check" id="check" />
</body>
</html>
But when I'm trying to test eg: apple or #apple always write "true". 但是，当我试图测试例如：apple或#apple总是写“真”。
What should I do? 我该怎么办？
Thanks! 谢谢！
3 个解决方案
解决方案1
1 2014-04-19 14:51:36
Should be: 应该：
var valid_qwe = /^[a-z0-9-]+$/;
Three changes here: 这里有三个变化：
the pattern itself now is
one or more characters of the given range(note that+quantifier after the brackets);模式本身现在是one or more characters of the given range（注意括号后面的+量词）;it's anchored both to the end (with
$) and the beginning (with^) of the string;它固定在字符串的末尾（带$）和开头（带^）;no need to escape
-within the character range if it's the last or the first symbol of it.无需逃避-在角色范围内，如果它是它的最后一个或第一个符号。
Finally, I'd rather see all the variables used within that function of yours localized - hence var . 最后，我宁愿看到你本地函数中使用的所有变量本地化 - 因此var 。
解决方案2
1 已采纳 2014-04-19 14:51:47
你的Regexp测试最后一个字符是否在这些约束内，尝试使用/^[a-z0-9\\-]+$/ 。
解决方案3
0 2014-04-19 14:56:30
Your regex is correct ( except that you are checking the last character ), but you're not matching the full string. 你的正则表达式是正确的（ 除了你检查最后一个字符 ），但你没有匹配完整的字符串。
Add a + to your regex, which means, match one or more of the previous token. 在正则表达式中添加一个+ ，表示匹配前一个标记中的一个或多个。
So your regex should be: 所以你的正则表达式应该是：
var valid_qwe = /[a-z0-9\-]+/
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