50 To build a regular expression from a variable in JavaScript, you'll need to use the RegExp constructor with a string parameter.

Another thing to note is that RegExp.prototype.exec() and RegExp.prototype.test() execute the regular expression on the provided string and return the first result.

String.match (regexp) is supposed to return an array with the matches. In my browser it doesn't (Safari on Mac returns only the full match, not the groups), but Regexp.exec (string) works.

Basically, this question is the same as the question here: Replace " ' " with " '' " in JavaScript Regexp isn't the only way to replace multiple occurrences of a substring, far from it. Think flexible, think split!

Jan 30, 2009 · The RegExp constructor takes 2 arguments: the expression, and flags. By using a template string in the expression, we can pass in the variable into the class, and it will transform it to …

I want to use JavaScript (I can also use jQuery) to do check whether a string matches the regex ^([a-z0-9]{5,})$, and get a true or false result. match() seems to check whether part of a string matches a …

Jan 26, 2017 · Is it possible to do something like this? var pattern = /some regex segment/ + /* comment here */ /another segment/; Or do I have to use new RegExp() syntax and concatenate a string? I'd …

Dec 14, 2015 · How can I check a JavaScript string is in a RegExp format, then convert it to RegExp? I found a way with RegExp, but the rule is too complex to make it right. function str2Regex(str){ var …

Is there a way to retrieve the (starting) character positions inside a string of the results of a regex match() in Javascript?

I want to extract a query string from my URL using JavaScript, and I want to do a case insensitive comparison for the query string name. Here is what I am doing: var results = new RegExp('[\\\\?&amp...