Is it valid html to have the following:
<form action="a">
<input.../>
<form action="b">
<input.../>
<input.../>
<input.../>
</form>
<input.../>
</form>
So when you submit "b" you only get the fields within the inner form. When you submit "a" you get all fields minus those within "b".
If it isn't possible, what workarounds for this situation are available?
A. It is not valid HTML nor XHTML
In the official W3C XHTML specification, Section B. "Element Prohibitions", states that:
"form must not contain other form elements."
http://www.w3.org/TR/xhtml1/#prohibitions
As for the older HTML 3.2 spec, the section on the FORMS element states that:
"Every form must be enclosed within a FORM element. There can be several forms in a single document, but the FORM element can't be nested."
B. The Workaround
There are workarounds using JavaScript without needing to nest form tags.
"How to create a nested form." (despite title this is not nested form tags, but a JavaScript workaround).
Answers to this StackOverflow question
Note: Although one can trick the W3C Validators to pass a page by manipulating the DOM via scripting, it's still not legal HTML. The problem with using such approaches is that the behavior of your code is now not guaranteed across browsers. (since it's not standard)
In case someone find this post here is a great solution without the need of JS. Use two submit buttons with different name attributes check in your server language which submit button was pressed cause only one of them will be sent to the server.
<form method="post" action="ServerFileToExecute.php">
<input type="submit" name="save" value="Click here to save" />
<input type="submit" name="delete" value="Click here to delete" />
</form>
The server side could look something like this if you use php:
<?php
if(isset($_POST['save']))
echo "Stored!";
else if(isset($_POST['delete']))
echo "Deleted!";
else
echo "Action is missing!";
?>
HTML 4.x & HTML5 disallow nested forms, but HTML5 will allow a workaround with "form" attribute ("form owner").
As for HTML 4.x you can:
You can answer your own question very easily by inputting the HTML code into the W3 Validator. (It features a text input field, you won't even have to put your code on a server...)
(And no, it won't validate.)
rather use a custom javascript-method inside the action attribute of the form!
eg
<html>
<head>
<script language="javascript" type="text/javascript">
var input1 = null;
var input2 = null;
function InitInputs() {
if (input1 == null) {
input1 = document.getElementById("input1");
}
if (input2 == null) {
input2 = document.getElementById("input2");
}
if (input1 == null) {
alert("input1 missing");
}
if (input2 == null) {
alert("input2 missing");
}
}
function myMethod1() {
InitInputs();
alert(input1.value + " " + input2.value);
}
function myMethod2() {
InitInputs();
alert(input1.value);
}
</script>
</head>
<body>
<form action="javascript:myMethod1();">
<input id="input1" type="text" />
<input id="input2" type="text" />
<input type="button" onclick="myMethod2()" value="myMethod2"/>
<input type="submit" value="myMethod1" />
</form>
</body>
</html>
No, it is not valid. But a "solution" can be creating a modal window outside of form "a" containing the form "b".
<div id="myModalFormB" class="modal">
<form action="b">
<input.../>
<input.../>
<input.../>
<button type="submit">Save</button>
</form>
</div>
<form action="a">
<input.../>
<a href="#myModalFormB">Open modal b </a>
<input.../>
</form>
It can be easily done if you are using bootstrap or materialize css. I'm doing this to avoid using iframe.
Because you allow for
all fields minus those within "b".
when submitting "a", the following would work, using regular web-forms without fancy JavaScript tricks:
Step 1. Put each form on its own web page.
Step 2. Insert an iframe wherever you want this sub-form to appear.
Step 3. Profit.
I tried to use a code-playground website to show a demo, but many of them prohibit embedding their websites in iframes, even within their own domain.
As workaround you could use formaction attribute on submit button. And just use different names on your inputs.
<form action="a">
<input.../>
<!-- Form 2 inputs -->
<input.../>
<input.../>
<input.../>
<input type="submit" formaction="b">
</form>
<input.../>
