regex - Regular expression in javascript with OR condition - Stack Overflow

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I need to create a regular expression that is able to determine //example or //www.example in the website URL . I get the url location of website by ,

var urlOfWeb = location.href ;

I created a regular expression in JavaScript which gives an irregular output when run multiple times . I tried it in firefox browser / console / Phpstorm IDE . Here is the expression ,

// The regular expression
    var expToLookFor = /(\/\/example|\/\/www\.example)/g;
// Using test method of Regexp object of javascript which gives bool result
expToLookFor.test("//example") ;
// Result : true
expToLookFor.test("//example") ;
// Result : false 

I need to create a regular expression that is able to determine //example or //www.example in the website URL . I get the url location of website by ,

var urlOfWeb = location.href ;

I created a regular expression in JavaScript which gives an irregular output when run multiple times . I tried it in firefox browser / console / Phpstorm IDE . Here is the expression ,

// The regular expression
    var expToLookFor = /(\/\/example|\/\/www\.example)/g;
// Using test method of Regexp object of javascript which gives bool result
expToLookFor.test("//example") ;
// Result : true
expToLookFor.test("//example") ;
// Result : false 

• javascript
• regex

Share Improve this question Follow asked Apr 6, 2015 at 16:36 Siddharth SharmaSiddharth Sharma 1,71122 gold badges1919 silver badges3535 bronze badges 3

• Get rid of the g flag in your regular expression. – Pointy Commented Apr 6, 2015 at 16:38
• 1 Also it would be simpler to do /\/\/(?:www\.)?example/ – Pointy Commented Apr 6, 2015 at 16:38
• 1 @siddarth there are many questions here regarding this issue. Please do a search before asking. – Avinash Raj Commented Apr 6, 2015 at 16:38

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1 Answer 1

Sorted by: Reset to default 9

Remove global flag from your regex to make it:

var expToLookFor = /(\/\/example|\/\/www\.example)/;

As g flag makes RegExp object remember it's last position lastIndex.

Better you refactor your regex to:

var expToLookFor = /\/\/(www\.)?example/;

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