FF+Firebug got an error "Regular Expression too complex", IE crashed and Chrome hung

According to this http://www.utexas.edu/its/help/domain-name-hosting-and/847 then I made this regular expression:

/^[a-z](\w+\.?\w*[a-z0-9]){5,17}@[a-z]((a-z0-9\-]{1,25}\.[a-z]{2,4})|([a-z0-9\-]{1,25}\.[a-z]{2,3}\.[a-z]{2,3}))$/;

And th开发者_开发技巧row this value:

asdfghjklzxcvbnmqwertyuiopasdfghjklzxcvbn@yahoo.com

Firefox + firebug says "Regular Expression too complex", IE Crashed and Chrome hung, is there something wrong with the regexp?

I use Javascript.

Missing [

/^[a-z](\w+\.?\w*[a-z0-9]){5,17}@[a-z]((

here [

a-z0-9\-]{1,25}\.[a-z]{2,4})|([a-z0-9\-]{1,25}\.[a-z]{2,3}\.[a-z]{2,3}))$/;

Try this (your solution has misprint):

^[a-z](\w+\.?\w*[a-z0-9]){5,17}@[a-z](([a-z0-9\-]{1,25}\.[a-z]{2,4})|([a-z0-9\-]{1,25}\.[a-z]{2,3}\.[a-z]{2,3}))$

I think you forgot [ in (a-z0-9\-]{1,25}

The actual issue here (ignoring the missing [) is that you have a greedy qualifier (/w+ and /w*) following by a range ({5,17})

What this means is:

• find any number of \w characters
• filter down to 5-17

The engine only does the filter after it finds the "any number", and gets very confused here...

It's a weird expression anyway: (\w+\.?\w*[a-z0-9]){5,17} The {5,17} should almost certainly be on part of that, not the entire thing.

what if someone has email address like john.doe@media.company.info or jane.doe@company.office?

try this:

(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])

http://regexpal.com/