Most are also unaware of the fact that you can distinguish the form button pressed by just giving them a name/value pair. E.g.
<form action="process" method="post">
...
<input type="submit" name="edit" value="Edit">
<input type="submit" name="delete" value="Delete">
<input type="submit" name="move_up" value="Move up">
<input type="submit" name="move_up" value="Move down">
</form>
In the server side, the actual button pressed can then be obtained by just checking the presence of the request parameter associated with the button name. If it is not null, then the button was pressed.
I've seen a lot of unnecessary JS hacks/workarounds for that, e.g. changing the form action or changing a hidden input value beforehand depending on the button pressed. It's simply astonishing.
Also, I've seen almost as many JS hacks/workarounds to gather the checked ones of multiple checkboxes like as in table rows. On every select/check of a table row the JS would add the row index to some commaseparated value in a hidden input element which would then be splitted/parsed further in the server side. That's result of unawareness that you can give multiple input elements the same name but a different value and that you can still access them as an array in the server side. E.g.
<tr><td><input type="checkbox" name="rowid" value="1"></td><td> ... </td></tr>
<tr><td><input type="checkbox" name="rowid" value="2"></td><td> ... </td></tr>
<tr><td><input type="checkbox" name="rowid" value="3"></td><td> ... </td></tr>
...
The unawareness would give each checkbox a different name and omit the whole value attribute. In some JS-hack/workaround-free situations I've also seen some unnecessarily overwhelming magic in the server side code to distinguish the checked items.
