Is there any way to validate inputs in the form using HMTL?
For example:
<input type="text" class="input-text error"
aria-required="true" placeholder="Enter your name *"
aria-invalid="true" required />
If user adds a special character to input, an error message saying "Characters are not allowed" should be shown below the input box.
First of all, client-side form validation is the greatest feature coming with the HTML5. Client-side form validation helps you to ensure data submitted matches the requirements. To get more detail about it you can visit here.
Important Note
Client-side form validation is an initial check, You should not use data coming from the form on the server side without checking it. It just a feature for good user experience. Because client-side validation is too easy to manipulate, so users can still easily send data that you do not want to on your server.
Solution
In this question, the best solution is; using HTML attribute pattern. The pattern attribute defines a regular expression the form control's value should match. To get more detail about pattern attribute you can visit the this page.
Below regexp you need.
^[a-zA-Z0-9]{5,12}$
It works like that;
It should contains only alphanumeric.
Minumum 5 and maximum 10
character.
You can use below code to integrate it with input field.
<form action="">
<input type="text" name="name" required
pattern="[a-zA-Z0-9]{5,12}" title="No special character">
<input type="submit">
</form>
Usually, to check inputs from html tags, you can create a javascript function to check your needs which is called everytime the user type in your input with the "onkeyup()" function.
The "onkeyup" keyword will trigger the function everytime user type in your field
<input type="text" onkeyup="myFunctionToCheck()">
<script>
myFunctionToCheck(){
//Here check your needs
}
</script>
Related
I have a button that is this <button id="btnSubmit">Submit</button> the problem is, I want the form tags to use this id so that is designed the way I want. And also this code, I have a few questions.
<form action="demo_form.php" method="get">
First name: <input type="text" name="fname"><br>
Last name: <input type="text" name="lname"><br>
<input type="submit" value="Submit">
</form>
what is the action="demo_form.php",input type="submit" do? And does the input type has any other "What do you call this stuff" besides submit?
The action="demo_form.php" sets the action, in this case, "navigate to file demo_form.php and send it the data".
<input type="submit" (...) > creates and element which submits the form e.g. executes the "action".
The method sets the way the data is submitted to the target of the action ("form_demo.php"), in this case get, which allows you to refer to the submitted data as $GET["name"] in PHP.
Possible input types are listed here.
You either give your <input type="submit" (...) > the id="btnSubmit" property or use javascript to submit the form after an event has been triggered.
MOr info on that is available here (i short: document.<get_the_form_element>.submit();).
I suggest you to take a look at this link. It describes all the basic concepts about how using forms. And you can also find a lot of information by Googling it.
The action attribute
The action attribute defines the action to be performed when the form is submitted.
The common way to submit a form to a server, is by using a submit button.
The input attribute
<input type="submit"> defines a button for submitting a form to a form-handler.
The form-handler is typically a server page with a script for processing input data.
If i understand your question correctly, these are my answers.
action
The action attribute describes the page to which the contents of the form are sent to. So if you have a sign up form with an input for an email, the text that is typed will be sent to the action path. It will be sent using the method described in the method attribute. So you can find your values in either the $_POST variable, or the $_GET variable, get is easy for being able to share the url and post is great for private information.
input
The input element is the actual way to input information (who guessed it). You've got an input of the type text for just text input, you've got checkbox for a true or false input and way way more see: w3schools
why don't you use
<input type="submit" value="Submit" id="btnSubmit">
Or if you want to use a button
<button id="btnSubmit">Submit</button>
Then from jquery or js you can submit the form.
And for this question,
what is the action="demo_form.php",input type="submit" do?
You should probably google it out. This is so basic.
Anyway, just a concise explanation:
action is the attribute where you will specify the code that will handle the form data submitted and input type="submit" will display a button in the page, clicking on it will submit the form.
There are a lot of types in input, the most common ones are
text
password
submit
I have a form:
<form method="GET">
<input type="text" value="hello" name="myname" />
</form>
If this form is submitted, I will end up at:
example.com/?myname=hello
What I would prefer is that when this gets submitted, I end up at:
example.com/hello
Is this possible?
No, you cannot change the way form submission works in HTML. (Using JavaScript, you can do transactions in a different way, without using HTML form submission.) When using method="GET", the URL gets constructed in a specific way; when using method="POST", the URL does not contain submitted data at all (it is sent outside the URL).
There is a trick that changes form submission in one way, but not quite the way you want. If the name of a control is isindex, then the control name and the equals sign are omitted; but the question mark is still there. That is, <input type="text" value="hello" name="isindex" /> would result in http://www.example.com/?hello. And Chrome has broken this when they removed the remainders of support to the isindex element.
If, for some special reason, you really need to make a form create requests like http://example.com/hello, then the simplest way is to set up a very simple server-side script that accepts normal requests that result from HTML forms and just passes them forward after modifying the URL in a simple way.
I was always confused about what the 'name' attribute did in html forms. From the textbook I read (html and css, design and build webpages by John Duckett), this is what it said about the 'name' attribute.
When users enter information
into a form, the server needs to
know which form control each
piece of data was entered into.
(For example, in a login form, the
server needs to know what has
been entered as the username
and what has been given as the
password.) Therefore, each form
control requires a name attribute.
The value of this attribute
identifies the form control and is
sent along with the information
they enter to the server.
From reading this, I always thought that, say in the database there is a field called "theUsersPasswordField" and a field called "theUsersUsernameField". I thought that, suppose there is a registration form, then the form would be like:
<form action="aURL" method="post">
<p>Please enter what you want your Username to be:</p>
<input type="submit" name="theUsersUsernameField" />
<p>Please enter what you want your Password to be:</p>
<input type="password" name="theUsersPasswordField" />
</form>
and then this way, when the information is sent to the database, it will know which information to put in the 'theUsersPasswordField" and which information to put in the "theUsersUesrnameField". Am I wrong?
What does name="next" mean? I see it often when I look at html forms, for example, here in this Django tutorial I am doing:
<form method="post" action=".">
<p><label for="id_username">Username:</label></p>
<p><label for="id_password">Password:</label></p>
<input type="hidden" name="next" value="/" />
<input type="submit" value="login" />
</form>
In the tutorial I am doing, it says that
The html form contains a submit button and a hidden
field called next. This hidden variable contains a URL that tells the view where to
redirect the user after they have successfully logged in
now, how is 'next' a url? When I run the code, the form does in fact successfully redirect to the main page, but how does it know to redirect to the main page? Why does name='next'?
And how does the server know which information to treat as the username and which information to treat as the password? I though that that is what the 'name' attribute is used for?
The name attribute in a control element like input assigns a name to the control. It has two basic effects: 1) a control needs a name in order to be “successful”, which means that a name=value pair from it will be included into the form data when the form is submitted; and 2) the attribute specifies what will be included as the first part of the name=value pair.
It is entirely up to the server-side form handler what (if anything) it will do with the name=value pairs in the form data. They might have a simple correspondence in some database, but that’s just one possibility. And form handling need not be database-based at all.
The name attribute values have no predefined meaning in HTML. They are just strings selected for use in this context, and they may be descriptive or mnemonic, or they may not.
However, the choice of name attribute values may have side effects. Browsers may give the user a menu of previously entered data so that if you fill e.g. several forms (possibly in different sites) that have a control named email, you might be able to enter your email address just once and then accept whatever the browser suggests as input. This may be seen as a convenience or as a threat to data security. There is proposed set of “standard” names for many purposes in HTML5 CR.
For completeness, it needs to be added that in browser practice and according to HTML5 CR description of name, two names have a special meaning: _charset_ and isindex.
The name next is in no way special, but in this context, it appears to specify the next page to move to. It is defined for a hidden field, so it takes effect independently of user input.
and then this way, when the information is sent to the database, it will know which information to put in the 'theUsersPasswordField" and which information to put in the "theUsersUesrnameField". Am I wrong?
You have to write a script (for example in php) that will put the right values from your form (they are in the $_POST array) into the databse.
in your example $_POST['theUsersUsernameField'] will hold the username
<form method="post" action=".">
<p><label for="id_username">Username:</label></p>
<p><label for="id_password">Password:</label></p>
<input type="hidden" name="next" value="/" />
<input type="submit" value="login" />
</form>
how is 'next' a url?
next is not the url.
the action="." is the url to wich the form redirects.
/ is the value that the script will evaluate to see what it has to do. (Normally you will have to change this into something else like 'check password')
In the $_POST[] array there will be a key $_POST['next'] and the value will be /
I am not familiar with Django but I hope this helps
Is there a way to use HTML5's built in form validation in input elements that are NOT required? I.e. is there a way to validate an HTML5 input if and only if the field has an actual value?
For example, I'd like to use the following markup to check whether some_name is a URL if and only if the user actually enters a value in the input. If the user leaves the input blank, the form should still be able to submit as usual.
<input type="url" name="some_name" [some attribute or additional markup?]/>
Thanks very much for your help.
Use the pattern attribute that accepts javascript regular expressions.
<input type="url" name="some_name" pattern="your regular expression"/>
Normally an HTML form sends query parameters as key-value pairs like this:
http://blabla/?something=something&this=that
But what I need is a form that generates a URL with one of the query keys omitted:
http://blabla/?something&this=that
As far as I can tell, a missing or empty name attribute does not quite provide what I expect:
<input type="hidden" name="" value="myvalue"/>
Leads to this, with an equals sign that I don't want:
http://blabla/?=myvalue
I know it's not good practice to do this, but I need to interface with an existing poorly-designed system.
If you need the attribute to not have a value, shouldn't you do something like this instead?
<input type="hidden" name="something" value=""/>
which would produce the URL http://blabla/?something=&this=that that you are looking for, only with the '=' after something. Or, just leave it out entirely (ie, do not define an input type hidden) and you would get the URLhttp://blabla/?this=that ...
Maybe I'm missing the point here, but either just don't submit that value or set it to null prior to submitting the form. It's not good practice to have an input without a name, so keep the name.
Obviously, we don't know how the script that accepts the form input is setup, but in my experiences unless some sort of crazy server-side validation was setup, it shouldn't bark at you.
These answers make sense logically, but unfortunately this system is very picky about which characters it will accept and any spurious equals signs give it trouble. It's an Innovative Interfaces library OPAC, by the way.
I figured out one way to do it, which is by not submitting the form at all but using JavaScript to inject the contents of the text box into a dynamically-generated URL and then opening that using window.location:
<form name="search_form" method="get" action="">
<input type="text" size="30" maxlength="100"/>
<input type="submit" value="Search" />
</form>
<script type="text/javascript">
window.onload = function() {
document.search_form.onsubmit = function() {
var term = document.search_form.elements[0].value;
var url = "http://blabla/search/X?d:(electronic books) and ("
+ term + ")&searchscope=1";
window.location = url;
}
}
</script>
I don't do much JavaScript and this will certainly cause alarm to anyone mindful of accessibility and web standards compliance. However, rest assured it is no worse than any of the rest of the javascriptaghetti that is part of this system.