Are JSP pages compatible with HTML5 syntax? - html

I'm working with Tomcat 9 and use a site, with a few JSP pages. I have Sheet.jsp, a self-posting page: it has a form, say F, containing two fields, A and B; there's also a submit button, S. A is an input field, B is readonly and shows the result.
I want to use HTML5, so I put at the beginning of Sheet.jsp.
So I wrote:
<form id=F action=POST>
<input type=Text id=A>
<input type=Text id=B readonly>
<input type=submit id=S>
</form>
I used "id" attribute, not "name" attribute, according to HTML5.
So doing, the page doesn't work.
If I write:
<form name=F action=POST>
<input type=Text name=A>
<input type=Text name=B readonly>
<input type=submit name=S>
</form>
the page works fine.
So, my question is: is there any compatibility issue between JSP pages and HTML5 ?
Perhaps JSP generates HTML4 text only ?
Thanks in advance. PS: I apologize if it's a known and already answered question, but I tried and wasn't able to find it.

Maybe I've solved the problem.
The name attribute is necessary when the form is submitted, and only input tags with the attribute name are submitted. Without the name attribute defined, nothing is submitted.
The id attribute can be used on the client side (e.g. into Javascript code), but not for submission.

Related

Required attribute in Html

can I use required attribute here? when I am not using form tag ? whether required works only inside form tag?
<label for="fname">First name:</label>
<input type="text" id="fname" name="fname" required>
No, as mentioned here:
The "required" attribute only works on form submit and since your
input has no form the browser does not know what to validate on
submit.
Here is also what W3C says:
When present, it specifies that an input field must be filled out before submitting the form.
So — assuming you aren't intending to use some sort of JS solution — no form, no required.

Weird behaviour of form element in bootstrap (gets removed from the DOM for some reason) [duplicate]

Is it possible to nest html forms like this
<form name="mainForm">
<form name="subForm">
</form>
</form>
so that both forms work? My friend is having problems with this, a part of the subForm works, while another part of it does not.
In a word, no. You can have several forms in a page but they should not be nested.
From the html5 working draft:
4.10.3 The form element
Content model:
Flow content, but with no form element descendants.
The HTML5 <input> form attribute can be the solution.
From http://www.w3schools.com/tags/att_input_form.asp:
The form attribute is new in HTML5.
Specifies which <form> element an <input> element belongs to. The value of this attribute must be the id attribute of a <form> element in the same document.
Scenario:
input_Form1_n1
input_Form2_n1
input_Form1_n2
input_Form2_n2
Implementation:
<form id="Form1" action="Action1.php" method="post"></form>
<form id="Form2" action="Action2.php" method="post"></form>
<input type="text" name="input_Form1_n1" form="Form1" />
<input type="text" name="input_Form2_n1" form="Form2" />
<input type="text" name="input_Form1_n2" form="Form1" />
<input type="text" name="input_Form2_n2" form="Form2" />
<input type="submit" name="button1" value="buttonVal1" form="Form1" />
<input type="submit" name="button2" value="buttonVal2" form="Form2" />
Here you'll find browser's compatibility.
It is possible to achieve the same result as nested forms, but without nesting them.
HTML5 introduced the form attribute. You can add the form attribute to form controls outside of a form to link them to a specific form element (by id).
https://www.impressivewebs.com/html5-form-attribute/
This way you can structure your html like this:
<form id="main-form" action="/main-action" method="post"></form>
<form id="sub-form" action="/sub-action" method="post"></form>
<div class="main-component">
<input type="text" name="main-property1" form="main-form" />
<input type="text" name="main-property2" form="main-form" />
<div class="sub-component">
<input type="text" name="sub-property1" form="sub-form" />
<input type="text" name="sub-property2" form="sub-form" />
<input type="submit" name="sub-save" value="Save" form="sub-form" />
</div>
<input type="submit" name="main-save" value="Save" form="main-form" />
</div>
The form attribute is supported by all modern browsers. IE does not support this though but IE is not a browser anymore, rather a compatibility tool, as confirmed by Microsoft itself: https://www.zdnet.com/article/microsoft-security-chief-ie-is-not-a-browser-so-stop-using-it-as-your-default/. It's about time we stop caring about making things work in IE.
https://caniuse.com/#feat=form-attribute
https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fae-form
From the html spec:
This feature allows authors to work around the lack of support for
nested form elements.
The second form will be ignored, see the snippet from WebKit for example:
bool HTMLParser::formCreateErrorCheck(Token* t, RefPtr<Node>& result)
{
// Only create a new form if we're not already inside one.
// This is consistent with other browsers' behavior.
if (!m_currentFormElement) {
m_currentFormElement = new HTMLFormElement(formTag, m_document);
result = m_currentFormElement;
pCloserCreateErrorCheck(t, result);
}
return false;
}
Plain html cannot allow you to do this. But with javascript you can be able to do that.
If you are using javascript/jquery you could classify your form elements with a class and then use serialize() to serialize only those form elements for the subset of the items you want to submit.
<form id="formid">
<input type="text" class="class1" />
<input type="text" class="class2">
</form>
Then in your javascript you could do this to serialize class1 elements
$(".class1").serialize();
For class2 you could do
$(".class2").serialize();
For the whole form
$("#formid").serialize();
or simply
$("#formid").submit();
If you're using AngularJS, any <form> tags inside your ng-app are replaced at runtime with ngForm directives that are designed to be nested.
In Angular forms can be nested. This means that the outer form is valid when all of the child forms are valid as well. However, browsers do not allow nesting of <form> elements, so Angular provides the ngForm directive which behaves identically to <form> but can be nested. This allows you to have nested forms, which is very useful when using Angular validation directives in forms that are dynamically generated using the ngRepeat directive. (source)
Another way to get around this problem, if you are using some server side scripting language that allows you to manipulate the posted data, is to declare your html form like this :
<form>
<input name="a_name"/>
<input name="a_second_name"/>
<input name="subform[another_name]"/>
<input name="subform[another_second_name]"/>
</form>
If you print the posted data (I will use PHP here), you will get an array like this :
//print_r($_POST) will output :
array(
'a_name' => 'a_name_value',
'a_second_name' => 'a_second_name_value',
'subform' => array(
'another_name' => 'a_name_value',
'another_second_name' => 'another_second_name_value',
),
);
Then you can just do something like :
$my_sub_form_data = $_POST['subform'];
unset($_POST['subform']);
Your $_POST now has only your "main form" data, and your subform data is stored in another variable you can manipulate at will.
Hope this helps!
As Craig said, no.
But, regarding your comment as to why:
It might be easier to use 1 <form> with the inputs and the "Update" button, and use copy hidden inputs with the "Submit Order" button in a another <form>.
Note you are not allowed to nest FORM elements!
http://www.w3.org/MarkUp/html3/forms.html
https://www.w3.org/TR/html4/appendix/changes.html#h-A.3.9 (html4 specification notes no changes regarding nesting forms from 3.2 to 4)
https://www.w3.org/TR/html4/appendix/changes.html#h-A.1.1.12 (html4 specification notes no changes regarding nesting forms from 4.0 to 4.1)
https://www.w3.org/TR/html5-diff/ (html5 specification notes no changes regarding nesting forms from 4 to 5)
https://www.w3.org/TR/html5/forms.html#association-of-controls-and-forms comments to "This feature allows authors to work around the lack of support for nested form elements.", but does not cite where this is specified, I think they are assuming that we should assume that it's specified in the html3 specification :)
You can also use formaction="" inside the button tag.
<button type="submit" formaction="/rmDog" method='post' id="rmDog">-</button>
This would be nested in the original form as a separate button.
A simple workaround is to use a iframe to hold the "nested" form.
Visually the form is nested but on the code side its in a separate html file altogether.
Even if you could get it to work in one browser, there's no guarantee that it would work the same in all browsers. So while you might be able to get it to work some of the time, you certainly wouldn't be able to get it to work all of the time.
While I don't present a solution to nested forms (it doesn't work reliably), I do present a workaround that works for me:
Usage scenario: A superform allowing to change N items at once. It has a "Submit All" button at the bottom. Each item wants to have its own nested form with a "Submit Item # N" button. But can't...
In this case, one can actually use a single form, and then have the name of the buttons be submit_1..submit_N and submitAll and handle it servers-side, by only looking at params ending in _1 if the name of the button was submit_1.
<form>
<div id="item1">
<input type="text" name="foo_1" value="23">
<input type="submit" name="submit_1" value="Submit Item #1">
</div>
<div id="item2">
<input type="text" name="foo_2" value="33">
<input type="submit" name="submit_2" value="Submit Item #2">
</div>
<input type="submit" name="submitAll" value="Submit All Items">
</form>
Ok, so not much of an invention, but it does the job.
Use empty form tag before your nested form
Tested and Worked on Firefox, Chrome
Not Tested on I.E.
<form name="mainForm" action="mainAction">
<form></form>
<form name="subForm" action="subAction">
</form>
</form>
EDIT by #adusza: As the commenters pointed out, the above code does not result in nested forms. However, if you add div elements like below, you will have subForm inside mainForm, and the first blank form will be removed.
<form name="mainForm" action="mainAction">
<div>
<form></form>
<form name="subForm" action="subAction">
</form>
</div>
</form>
Although the question is pretty old and I agree with the #everyone that nesting of form is not allowed in HTML
But this something all might want to see this
where you can hack(I'm calling it a hack since I'm sure this ain't legitimate) html to allow browser to have nested form
<form id="form_one" action="http://apple.com">
<div>
<div>
<form id="form_two" action="/">
<!-- DUMMY FORM TO ALLOW BROWSER TO ACCEPT NESTED FORM -->
</form>
</div>
<br/>
<div>
<form id="form_three" action="http://www.linuxtopia.org/">
<input type='submit' value='LINUX TOPIA'/>
</form>
</div>
<br/>
<div>
<form id="form_four" action="http://bing.com">
<input type='submit' value='BING'/>
</form>
</div>
<br/>
<input type='submit' value='Apple'/>
</div>
</form>
JS FIDDLE LINK
http://jsfiddle.net/nzkEw/10/
About nesting forms: I spent 10 years one afternoon trying to debug an ajax script.
my previous answer/example didn't account for the html markup, sorry.
<form id='form_1' et al>
<input stuff>
<submit onClick='ajaxFunction(That_Puts_form_2_In_The_ajaxContainer)'>
<td id='ajaxContainer'></td>
</form>
form_2 constantly failed saying invalid form_2.
When I moved the ajaxContainer that produced form_2 <i>outside</i> of form_1, I was back in business. It the answer the question as to why one might nest forms. I mean, really, what's the ID for if not to define which form is to be used? There must be a better, slicker work around.
No you cannot have a nested form. Instead you can open up a Modal that contains form and perform Ajax form submit.
Really not possible...
I couldn't nest form tags...
However I used this code:
<form>
OTHER FORM STUFF
<div novalidate role="form" method="post" id="fake_form_id_0" data-url="YOUR_POST_URL">
THIS FORM STUFF
</div>
</form>
with {% csrf_token %} and stuff
and applied some JS
var url = $(form_id).attr("data-url");
$.ajax({
url: url,
"type": "POST",
"data": {
'csrfmiddlewaretoken': '{{ csrf_token }}',
'custom-param-attachment': 'value'
},
success: function (e, data) {
if (e.is_valid) {
DO STUFF
}
}
});
Today, I also got stuck in same issue, and resolve the issue I have added a user control and
on this control I use this code
<div class="divformTagEx">
</div>
<asp:Literal runat="server" ID="litFormTag" Visible="false">
'<div> <form style="margin-bottom: 3;" action="http://login.php" method="post" name="testformtag"></form> </div>'</asp:Literal>
and on PreRenderComplete event of the page call this method
private void InitializeJavaScript()
{
var script = new StringBuilder();
script.Append("$(document).ready(function () {");
script.Append("$('.divformTagEx').append( ");
script.Append(litFormTag.Text);
script.Append(" )");
script.Append(" });");
ScriptManager.RegisterStartupScript(this, GetType(), "nestedFormTagEx", script.ToString(), true);
}
I believe this will help.
Before I knew I wasn't supposed to do this I had nested forms for the purpose of having multiple submit buttons. Ran that way for 18 months, thousands of signup transactions, no one called us about any difficulties.
Nested forms gave me an ID to parse for the correct action to take. Didn't break 'til I tried to attach a field to one of the buttons and Validate complained. Wasn't a big deal to untangle it--I used an explicit stringify on the outer form so it didn't matter the submit and form didn't match. Yeah, yeah, should've taken the buttons from a submit to an onclick.
Point is there are circumstances where it's not entirely broken. But "not entirely broken" is perhaps too low a standard to shoot for :-)
[see thecode.. code format below ]2simple trick
simply dont use other inside another form tag, please use the same elements without using form tag.
see example below
"" dont use another form // just recall the enter image description hereelement in it""

POST Checkbox value in HTML

I want to post checkbox values to server using html. But my code retrieves nothing. Please help.
<form action="Default2.aspx" method="post" >
<input type="checkbox" name="attempt" value="101"> I'st attempt<br>
<input type="checkbox" name="attempt" value="102" checked> 2nd attempt<br>
<input type="submit" value="Submit">
</form>
They need ID's so they can be referred to and if this is a Web Forms website you need to also have the attribute runat="server" for both of them otherwise you won't be able to access them.
ASP.NET Page already has form element in the root, and you don't have insert it by self. If you use native HTML element in your ASP.NET page or control, you can get their values by using Request Object. See simple example here How-get-input-text-value-server-side-c.aspx
In plain HTML forms, checkbox input controls don't get included in the submission at all if the user left them unchecked. See this question: Does <input type="checkbox" /> only post data if it's checked?

Is it OK to have multiple HTML forms with the same name?

I have a valid reason for wanting to do this, but it's a long story so I'll forgot trying to explain why and just ask if it's OK to do.
I have a page where I need to have multiple forms with the same name, but I only want the form whose submit button is click to be submitted. For example, the following might be on my page:
<form name="input" action="" method="get">
Username: <input type="text" name="user" />
<input type="submit" value="Submit" />
</form>
text
<form name="input" action="" method="get">
Username: <input type="text" name="user" />
<input type="submit" value="Submit" />
</form>
text
<form name="input" action="" method="get">
Username: <input type="text" name="user" />
<input type="submit" value="Submit" />
</form>
Is this acceptable?
Regarding the HTML 4.01 specication, you can use form elements with the same name attribute, as there is no uniqueness requirement on them. Doing so defeats the purpose of such attributes, though. They are meant for making it easier to refer to forms in client-side scripting: if you have <form name=foo>, then document.foo refers to that form.
It is undefined what happens when same name attribute is used, but what browsers seem to do is to return an array. In your example, document.foo would be a 3-element array, with document.foo[0] being the first form. But this is not useful, since (assuming there are no other forms in the document) you could use document.forms[0], with a well-defined meaning.
The name attribute itself is outdated for form elements (but not for form fields, where it keeps being essential). The HTML 4.01 spec clause on form says:
“name = cdata [CI]
This attribute names the element so that it may be referred to from style sheets or scripts. Note. This attribute has been included for backwards compatibility. Applications should use the id attribute to identify elements.”
In the HTML5 drafts, even the formal rules disallow the use of the same name attribute. The HTML5 clause on the name attribute on form says that its value “must be unique amongst the form elements in the forms collection that it is in, if any”. This is a confusing formulation, but it is safest to assume that it must be unique within the form elements of a document.
Yes it is allowed, only id's must be unique. I wouldn't recommend it however, why even put yourself in a position to be confused down the road.
The name attribute only defines what each form field element will be represented as when sent to the server.
It is also ok in HTML5. Only the name must be unique inside the form itself.
See the docs: "The value must not be the empty string, and the value must be unique amongst the form elements in the forms collection that it is in, if any."
When the user clicks a submit button, only that form will be taken in action. Still, it should be better to name them so that you are not confused :)

When should I use the name attribute in HTML4/HTML5?

I know by reading the W3C documentation for HTML4.01 and HTML5 that the "name" attribute originally existed as a property of the <a> tag to permit people to link to an anchor point within a document.
However, now that all major browser vendors allow linking to any HTML element within a document via the "id" attribute, is there still any real use for the "name" attribute? If so, how should I be using the "name" attribute?
One thing that comes to mind are radio buttons: you have to use name to specify which ones are part of the same group.
<form>
<input type="radio" name="sex" value="male" /> Male<br />
<input type="radio" name="sex" value="female" /> Female
</form>
The name attribute is required, I think, on input elements (and their friends)...
<input type="text" name="email" value="" />
Good question... As mentioned in other answers one obvious use is for radio buttons so that only one radio button can be selected at a time, as you can see in jQuery radio buttons - choose only one?
Along with this, in ASP.Net MVC I have found another use of the name attribute. Refer
MVC which submit button has been pressed
<input name="submit" type="submit" id="submit" value="Save" />
<input name="submit" type="submit" id="process" value="Process" />
From http://www.w3schools.com/tags/att_button_name.asp
The name attribute specifies the name for a element.
The name attribute is used to reference form-data after the form has been submitted, or to reference the element in a JavaScript.
Tip: Several elements can share the same name. This allows you to have several buttons with equal names, which can submit different values when used in a form.
Other References
HTML5 How To Skip Navigation When Name Attribute Is Obsolete
HTML5 Obsolete features
HTML input - name vs. id