In URL-encoded text, alphanumeric characters and the dollar sign, minus sign, underscore, period, exclamation mark, asterisk, left and right parentheses, and comma are transmitted as normal text.
All other characters (such as quotation marks and spaces) are encoded to facilitate their transmission over the Internet. In the encoded text, these characters are replaced with a percent sign followed by a two-digit hexadecimal number representing the ASCII value of the original character. (For example, a space character would be replaced with %20 since 20 is the hexadecimal number for 32, which is the ASCII code for a space.)