How to pass % in a URL query string?

Question

I am trying to pass a string via HTTP request which has one of the character as % in the URL query string.

url = url + "?q=" + str + "&block=" + block;  // str contains the '%' character

But on the ColdFusion page where I'm sending this information is returning following error:

Element Q is undefined in URL.

How can I encode the % sign in a URL?

Answer 1

You should url-encode all the values you are passing as query parameters, but the url-encoding for % is %25

Update: if you're constructing the query parameters in javascript, you probably want to do:

url=url+"?q="+encodeURIComponent(str)+"&block="+encodeURIComponent(block)

(Updated again with ZeissS' very helpful suggestion to use encodeURIComponent instead of escape. See also http://xkr.us/articles/javascript/encode-compare/)