How to keep already-set GET parameter values on form submission?

Question

I have a URL : foo.php?name=adam&lName=scott, and in foo.php I have a form which gives me values of rectangleLength & re

Answer 1

Once, I needed sorting the results in a table keeping the search results coming from GET. I did like that:

unset($_GET['sort']); // sort param is removed, otherwise there will be created many sort params
$url = http_build_query($_GET);

echo "<a href='?".$url."&sort=title'>Title</a>";
echo "<a href='?".$url."&sort=author'>Author</a>";