URL's with percent signs??? Why?

Sometimes I'll copy a URL and it will contain percent signs and numbers.  Other times it won't  Why is this?
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Jeff DarlingDeveloper AnalystCommented:
The percent signs and numbers are url encoded strings.

URL Encoding replaces unsafe characters with % followed by their hex equivalent. That hex equivalent is the HEX value for the character being replaced.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Tom BeckCommented:
Detailed explanations all over the internet like this one. Includes a list of encoded characters:

Mark BullockQA EngineerCommented:
This encodes characters in the URL as number. Often these are reserved characters.
For example, let's say I wanted to pass a query parameter, answer, with a value of "a&b".
Your URL might look like:
Things would be confusing because the ampersand character has a special meaning (it separates two query parameters). So there are two query parameters in your URL: answer and b.
But you intended to send one query parameter.

So you URL encode the value to avoid this.
Jason C. LevineDon't talk to me.Commented:
Another common example:


%20 is a space:

http://domain.com/this is a bad idea.html
Dave BaldwinFixer of ProblemsCommented:
I like the explanation on this page: http://en.wikipedia.org/wiki/Percent-encoding
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Web Development

From novice to tech pro — start learning today.