JavaScript中的正则表达式不匹配字符串吗？

Question

I have this JavaScript code:

var textareas = document.getElementsByTagName('textarea');
var content = textareas[0].value;
var reg = new RegExp(/^.*[[]#.+#[]].*$/mgi);
var res = content.match(reg); // always null 

The content var contains a long multiline string that contains patterns like [#some text goes here#] . I tested the regex with some online testing tools and it works against the string. Using the regex in JavaScript fails though - any idea why?

Thanks!

Answer 1

How about this?

var content = 'foo\nhead [#some text goes here#] tail\nbar';
var reg = new RegExp(/\[#.+#\]/mgi);
var res = content.match(reg);

On execution, res contains the string '[#some text goes here#]' .

Note that I have escaped [ and ] . If they are not escaped, anything enclosed within them forms a character class .

Answer 2

You used [[] to escape [ , which is fine, but you can't use []] to escape ] because it the first ] ends the character class in the regex. This works fine:

/^.*\[#.+#\].*$/mgi

In the case that you only want the single block and not the entire line, use:

/\[#.+#\]/mgi

Answer 3

这应该捕获散列之间的文本（例如，“此处有一些文本”）：

var reg = /[^\[]*\[#([^\#]+)#\]/gims