preg_match url

[slimjim]

I have this code

if(preg_match("/http(s?):\/\//",$clicksurl)){
//good url and not missing the http://
}else{
 //bad url and is missing the http://
}  

How do I also make sure if it has www. in it and if it doesn't then its a bad url

[NogDog]

"/http(s?):\/\/www\./"

However, that begs the question as to why you are assuming that all the URLs you expect to be checking must have a 'www' sub-domain?

[bradgrafelman]

OR that even if a URL contains www. it may not be valid (ex. http://www.this:isn'tvalid!.com).