Regex to test if string begins with http or https

Question

I m trying to set a regexp which will check the start of a string  and if it contains either http    or https    it should match it   How can I do that  I m trying the following which isn t working      http  https

User · Answer

https           where      is match everything else after https

User · Answer

Making this case insensitive wasn t working in asp net so I just specified each of the letters   Here s what I had to do to get it working in an asp net RegularExpressionValidator    Hh  Tt  Tt  Pp  Ss            Notes      i  and using  whatever i didn t work probably because javascript hasn t brought in all case sensitive functionality Originally had   at beginning but it didn t matter  but the      did  Expression didn t work without      but did work without    Didn t need to escape the    though might be a good idea    Here s the full RegularExpressionValidator if you need it    lt asp RegularExpressionValidator ID  revURLHeaderEdit  runat  server       ControlToValidate  txtURLHeaderEdit       ValidationExpression   Hh  Tt  Tt  Pp  Ss               ErrorMessage  URL should begin with http    or https      gt   lt  asp RegularExpressionValidator gt

User · Answer

for start of the string pattern    for allowing 0 or 1 time repeat  ie   s   s can exist 1 time or no need to exist at all    is a special character in regex so it needs to be escaped by a backslash      https        test  https   www bbc co uk sport cricket       true    https        test  http   www bbc co uk sport cricket       true    https        test  ftp   www bbc co uk sport cricket       false

User · Answer

This should work    http https

User · Answer

http https         S   This works for me Not a regex specialist  but i will try to explain the awnser   http https    Parenthesis indicates a capture group   quot I quot  a OR statement          quot   quot  allows special characters  such as  quot   quot    S     Anything that is not whitespace until the next whitespace

User · Answer

This will work for URL encoded strings too     https            3A 2F 2F

User · Answer

Your use of    is incorrect -- note that    denotes a character class and will therefore only ever match one character   The expression   http  https   translates to  match a    an h  a t  a t  a p  a    or an s     Duplicate characters are ignored    Try this    https       If you really want to use alternation  use this syntax instead     http https

User · Answer

Case insensitive   var re   new RegExp    http https        i    var str    My String   var match   re test str

User · Answer

https       You might have to escape the forward slashes though  depending on context

[regex] Regex to test if string begins with http:// or https://

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