Escaping in a Query String
As you are probably aware HTML requires that the ampersade character & be typed out as &. This must also be done in URLs:
The address:
script.pl?task=1&category=happiness
becomes:
script.pl?task=1&category=happiness
URL contains an ampersade
What happens when the query string contains a ampersade? For example:
script.pl?task=1&category=bits & bytes
In the example above the category is "bits & bytes" but since query strings recognize the ampersade as a
field delimitor we have a problem. HTTP (which the descibes how a URL should look) has solution.
The ampersade that is not a delimitor in the query string should be escaped into URL encoding. As,
incidently, should spaces. An ampersade can be represented in a URL as %26. A space as %20.
Therefore, the solution to the problem above is:
script.pl?task=1&category=bits%20%26%20bytes
The anchor might look like this:
<a href='script.pl?task=1&category=bits%20%26%20bytes'>Show Category</a>
The follow table shows useful escape codes for use in URL query string.
| Normal Character | Encoding Character |
|---|---|
| (space) | %20 |
| & | %26 |
| ' (single quote) | %27 |
| " | %22 |
| ? | %3F |
| = | %3D |
| + | %2B |
| % | %25 |
If so, why not provide a link to it? Just copy the following to your web page:
<a href='http://upwithabang.com/articles/html-query-string-escapes.html'>
Escaping query strings
</a>
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