How to get the values from a form and prevent submission? - javascript

I have this simple form:
HTML
<form>
<label for="eName">Name</label>
<input id="eName" type="text" name="eName">
<label for="Email">Email</label>
<input id="Email" type="text" name="Email">
<button id="create" class="boton"
onclick="doSomething();" type="submit">Create!</button>
</form>
JS
function doSomething() {
var name, email;
name = document.getElementById("eName").value;
email = document.getElementById("Email").value;
putElementsIntoTheDOM(name, email);
}
When the user inputs some information I want to populate the DOM with the user input.
The example above works. But I think it can be done better. I just don't know how.
How can I wire the <button> so that when the user clicks it the form values are passed
to the function doSomething()?
Also, since I'm not sending the form values anywhere except populating the DOM, how can I
prevent the submission?
I've seen something like this but I can't get it too work.
<button id="create" class="boton" onclick="doSomething(this.form);"
type="submit">Create!</button>

If you don't want to send the form values anywhere, then you just need to remove type="submit" from your button.
Your example code works fine. I'm not sure what you mean by a 'better' way. More modern/idiomatic javascript would not be using the onclick attribute, but instead binding doSomething to the button. Using jQuery, that would look like:
$("#create").click(doSomething);

First of all you have to update your function declaration to be able to receive the variables you want to send
function doSomething(name,email) {
}
Secondly, if you have to send values of some fields to that function, you can do so on button click like this.
<button id="create" class="boton" onclick="doSomething(document.getElementById('eName').value,document.getElementById('Email').value);" type="submit">Create!</button>
However, using unobtrusive javascript is recommended, and for that jQuery is one of the options you can use for passing variables to your function neatly.

There is a difference between the type="submit" and type="button" that I didn't realize.
Also, the button and submit types react differently with onclick and onsubmit events.
For example
<form onclick="doSomething()">
<label for="eName">Name</label>
<input id="eName" type="text" name="eName">
<label for="Email">Email</label>
<input id="Email" type="text" name="Email">
<button id="create" class="boton" type="button">Create!</button>
</form>
Notice that at the top of the form there is onclick.
The onclick is fired whenever you focus on an input element, and of course if you click the button.
Changing the form to <form onsubmit="doSomething(); but not changing the type="button" doesn't do anything. Clicking the button doesn't trigger the function.
By changing the type="submit"and keeping the head <form onsubmit="doSomething(); triggers the function when the button is clicked. A nice added functionality to this is that if you have any <input ... required="required"> the submit will only work if those fields are filled in (and your form will let you know about the required fields).
To prevent the submission/refreshing (since I'm only populating the DOM with user input) adding return false at the form head prevents submission
<form onsubmit="doSomething(); return false">.
Finally, to get the form values adding this:
<form onsubmit="doSomething(this); return false> and then
function doSommething(formInfo) {
var name = formInfo.eName.value;
var email = formInfo.Email.value;
...
}

Related

i am using required html tag for input fields but its not working [duplicate]

I'm using HTML5 for validating fields. I'm submitting the form using JavaScript on a button click. But the HTML5 validation doesn't work. It works only when then input type is submit. Can we do anything other than using JavaScript validation or changing the type to submit?
This is the HTML code:
<input type="text" id="example" name="example" value="" required>
<button type="button" onclick="submitform()" id="save">Save</button>
I'm submitting the form in the function submitform().
The HTML5 form validation process is limited to situations where the form is being submitted via a submit button. The Form submission algorithm explicitly says that validation is not performed when the form is submitted via the submit() method. Apparently, the idea is that if you submit a form via JavaScript, you are supposed to do validation.
However, you can request (static) form validation against the constraints defined by HTML5 attributes, using the checkValidity() method. If you would like to display the same error messages as the browser would do in HTML5 form validation, I’m afraid you would need to check all the constrained fields, since the validityMessage property is a property of fields (controls), not the form. In the case of a single constrained field, as in the case presented, this is trivial of course:
function submitform() {
var f = document.getElementsByTagName('form')[0];
if(f.checkValidity()) {
f.submit();
} else {
alert(document.getElementById('example').validationMessage);
}
}
You should use form tag enclosing your inputs. And input type submit.
This works.
<form id="testform">
<input type="text" id="example" name="example" required>
<button type="submit" onclick="submitform()" id="save">Save</button>
</form>
Since HTML5 Validation works only with submit button you have to keep it there.
You can avoid the form submission though when valid by preventing the default action by writing event handler for form.
document.getElementById('testform').onsubmit= function(e){
e.preventDefault();
}
This will give your validation when invalid and will not submit form when valid.
I may be late, but the way I did it was to create a hidden submit input, and calling it's click handler upon submit. Something like (using jquery for simplicity):
<input type="text" id="example" name="example" value="" required>
<button type="button" onclick="submitform()" id="save">Save</button>
<input id="submit_handle" type="submit" style="display: none">
<script>
function submitform() {
$('#submit_handle').click();
}
</script>
I wanted to add a new way of doing this that I just recently ran into. Even though form validation doesn't run when you submit the form using the submit() method, there's nothing stopping you from clicking a submit button programmatically. Even if it's hidden.
Having a form:
<form>
<input type="text" name="title" required />
<button style="display: none;" type="submit" id="submit-button">Not Shown</button>
<button type="button" onclick="doFancyStuff()">Submit</button>
</form>
This will trigger form validation:
function doFancyStuff() {
$("#submit-button").click();
}
Or without jQuery
function doFancyStuff() {
document.getElementById("submit-button").click();
}
In my case, I do a bunch of validation and calculations when the fake submit button is pressed, if my manual validation fails, then I know I can programmatically click the hidden submit button and display form validation.
Here's a VERY simple jsfiddle showing the concept:
https://jsfiddle.net/45vxjz87/1/
Either you can change the button type to submit
<button type="submit" onclick="submitform()" id="save">Save</button>
Or you can hide the submit button, keep another button with type="button" and have click event for that button
<form>
<button style="display: none;" type="submit" >Hidden button</button>
<button type="button" onclick="submitForm()">Submit</button>
</form>
Try with <button type="submit"> you can perform the functionality of submitform() by doing <form ....... onsubmit="submitform()">
2019 update: Reporting validation errors is now made easier than a the time of the accepted answer by the use of HTMLFormElement.reportValidity() which not only checks validity like checkValidity() but also reports validation errors to the user.
The HTMLFormElement.reportValidity() method returns true if the element's child controls satisfy their validation constraints. When false is returned, cancelable invalid events are fired for each invalid child and validation problems are reported to the user.
Updated solution snippet:
function submitform() {
var f = document.getElementsByTagName('form')[0];
if(f.reportValidity()) {
f.submit();
}
}
HTML5 Validation Work Only When button type will be submit
change --
<button type="button" onclick="submitform()" id="save">Save</button>
To --
<button type="submit" onclick="submitform()" id="save">Save</button>
Try this out:
<script type="text/javascript">
function test
{
alert("hello world"); //write your logic here like ajax
}
</script>
<form action="javascript:test();" >
firstName : <input type="text" name="firstName" id="firstName" required/><br/>
lastName : <input type="text" name="lastName" id="lastName" required/><br/>
email : <input type="email" name="email" id="email"/><br/>
<input type="submit" value="Get It!" name="submit" id="submit"/>
</form>

validate and submit html form required inputs using javascript

I have a form which contains inputs with required tag. It normally validates when I click on an input of type submit.
But I wanted to be able to initiate that process programmatically using javascript. or when an element outside of the form is clicked.
Is this possible? how can I do this?
function validateAndSubmit(){
//what can I do here to initiate same process?
//tried
document.querySelector("form").submit() //this one submits without validating
document.querySelector("#submitter").click() //no such function as this
}
<form>
<input required placeholder="name"/>
<input id="submitter" type="submit"/>
</form>
<button onClick=validateAndSubmit()>Send</button>
I want to do this from other event handler functions too. Is there a way to do this?
Thanks
You have to first focus on the form with the focus() method:
function validateAndSubmit(){
document.querySelector("form").focus()
document.querySelector("#submitter").click()
}
<form>
<input required placeholder="name"/>
<input id="submitter" type="submit"/>
</form>
<button onClick=validateAndSubmit()>Send</button>

Javascript function on submit externally?

I'm looking to create a Chrome extension for a new tab page. I've written the page and have it working only I'm having a problem with moving my Javascript from inline to external.
Current index.html is looking like this:
<script>
function process()
{
var url="https://www.google.co.uk/search?q=" + document.getElementById("goog").value;
location.href=url;
return false;
}
</script>
<div class="container">
<form onSubmit="return process();">
<input type="text" class="form-control" id="goog" placeholder="Google Search">
<input type="submit" style="display:none"/>
</form>
I've tried a few different methods of moving this into an external file but I'm not great with Javascript. I'd imagine I would need to use an event listener of some kind. I've tried placing this in search.js:
var form = document.getElementById("search");
form.addEventListener("submit", function() {
var url="https://www.google.co.uk/search?q=" + document.getElementById("goog").value;
location.href=url;
return false;
});
With this amended html:
<form id="search">
<input type="text" class="form-control" id="goog" placeholder="Google Search">
<input type="submit" style="display:none"/>
</form>
But to no avail. Can anyone help?
You are attaching the 'submit' event to the text input element.
You should instead attach it to the form, as it's the form what gets submitted, not only that particular input. (You already do it correctly on your current index.html document).
You can do this adding an id to the form element:
<form id="your-form-id">
and then attaching the event to it like you're already doing:
var form = document.getElementById("your-form-id");
form.addEventListener("submit", function() { ...
Also, note that unless you've changed your html while moving the JS code to an external file, on the 'submit' event callback you're trying to get the search string from an element with id="url" while your text input element has id="goog", so you won't be able to retrieve it.
EDIT:
The issue seems to be that the form submit gets executed and you're redirected to the same page with a new blank input before your code can be run.
You can avoid this calling preventDefault() on the event when receiving it so the form is not submitted and your code is run, instead of returning false at the end.
form.addEventListener("submit", function(event) {
event.preventDefault();
... your code ...
I've noticed that it's possible without any Javascript. I can make a form with a method of GET and pass the contents of the form into the GET request like below:
<form method="GET" action="https://google.co.uk/search">
<input type="text" name="q" class="form-control" placeholder="Google Search">
<input type="Submit" style="display:none">
</form>
The above solution is correct but using this avoids any Javascript whatsoever.

Validate input type=number min=... single field, no form [duplicate]

I'm using HTML5 for validating fields. I'm submitting the form using JavaScript on a button click. But the HTML5 validation doesn't work. It works only when then input type is submit. Can we do anything other than using JavaScript validation or changing the type to submit?
This is the HTML code:
<input type="text" id="example" name="example" value="" required>
<button type="button" onclick="submitform()" id="save">Save</button>
I'm submitting the form in the function submitform().
The HTML5 form validation process is limited to situations where the form is being submitted via a submit button. The Form submission algorithm explicitly says that validation is not performed when the form is submitted via the submit() method. Apparently, the idea is that if you submit a form via JavaScript, you are supposed to do validation.
However, you can request (static) form validation against the constraints defined by HTML5 attributes, using the checkValidity() method. If you would like to display the same error messages as the browser would do in HTML5 form validation, I’m afraid you would need to check all the constrained fields, since the validityMessage property is a property of fields (controls), not the form. In the case of a single constrained field, as in the case presented, this is trivial of course:
function submitform() {
var f = document.getElementsByTagName('form')[0];
if(f.checkValidity()) {
f.submit();
} else {
alert(document.getElementById('example').validationMessage);
}
}
You should use form tag enclosing your inputs. And input type submit.
This works.
<form id="testform">
<input type="text" id="example" name="example" required>
<button type="submit" onclick="submitform()" id="save">Save</button>
</form>
Since HTML5 Validation works only with submit button you have to keep it there.
You can avoid the form submission though when valid by preventing the default action by writing event handler for form.
document.getElementById('testform').onsubmit= function(e){
e.preventDefault();
}
This will give your validation when invalid and will not submit form when valid.
I may be late, but the way I did it was to create a hidden submit input, and calling it's click handler upon submit. Something like (using jquery for simplicity):
<input type="text" id="example" name="example" value="" required>
<button type="button" onclick="submitform()" id="save">Save</button>
<input id="submit_handle" type="submit" style="display: none">
<script>
function submitform() {
$('#submit_handle').click();
}
</script>
I wanted to add a new way of doing this that I just recently ran into. Even though form validation doesn't run when you submit the form using the submit() method, there's nothing stopping you from clicking a submit button programmatically. Even if it's hidden.
Having a form:
<form>
<input type="text" name="title" required />
<button style="display: none;" type="submit" id="submit-button">Not Shown</button>
<button type="button" onclick="doFancyStuff()">Submit</button>
</form>
This will trigger form validation:
function doFancyStuff() {
$("#submit-button").click();
}
Or without jQuery
function doFancyStuff() {
document.getElementById("submit-button").click();
}
In my case, I do a bunch of validation and calculations when the fake submit button is pressed, if my manual validation fails, then I know I can programmatically click the hidden submit button and display form validation.
Here's a VERY simple jsfiddle showing the concept:
https://jsfiddle.net/45vxjz87/1/
Either you can change the button type to submit
<button type="submit" onclick="submitform()" id="save">Save</button>
Or you can hide the submit button, keep another button with type="button" and have click event for that button
<form>
<button style="display: none;" type="submit" >Hidden button</button>
<button type="button" onclick="submitForm()">Submit</button>
</form>
Try with <button type="submit"> you can perform the functionality of submitform() by doing <form ....... onsubmit="submitform()">
2019 update: Reporting validation errors is now made easier than a the time of the accepted answer by the use of HTMLFormElement.reportValidity() which not only checks validity like checkValidity() but also reports validation errors to the user.
The HTMLFormElement.reportValidity() method returns true if the element's child controls satisfy their validation constraints. When false is returned, cancelable invalid events are fired for each invalid child and validation problems are reported to the user.
Updated solution snippet:
function submitform() {
var f = document.getElementsByTagName('form')[0];
if(f.reportValidity()) {
f.submit();
}
}
HTML5 Validation Work Only When button type will be submit
change --
<button type="button" onclick="submitform()" id="save">Save</button>
To --
<button type="submit" onclick="submitform()" id="save">Save</button>
Try this out:
<script type="text/javascript">
function test
{
alert("hello world"); //write your logic here like ajax
}
</script>
<form action="javascript:test();" >
firstName : <input type="text" name="firstName" id="firstName" required/><br/>
lastName : <input type="text" name="lastName" id="lastName" required/><br/>
email : <input type="email" name="email" id="email"/><br/>
<input type="submit" value="Get It!" name="submit" id="submit"/>
</form>

How do I detect how a form was submitted via JavaScript?

I have a form with multiple submit buttons and I'm listening for the 'submit' event via JavaScript. I want to know which submit button or form field (if the user pressed 'Enter/Return') triggered the submit event. Is there a way to get the HTML element that the user clicked on or pressed 'Enter/Return' in?
Update since people aren't understanding me:
This is via JavaScript before the form is submitted. No server-side detection allowed. I also need to handle the form being submitted via the user pressing Enter or Return.
Code
<form action="" method="POST">
<input type="text" name="first_name">
<input type="text" name="item">
<input type="submit" value="Add item">
<input type="submit" value="Submit">
</form>
Clicking 'Add Item' or pressing Return/Enter inside name="item" will add another form field.
Final Note
As far as I can tell, there isn't a way to detect which form field triggered a form submission. If you need to prevent submitting a form that has multiple buttons and/or from Enter/Return, you'll need to use <input type="button"> and bind event handlers to the form fields you want to stop form submission from.
If you have multiple submit buttons, the way you can tell is by giving each of them a unique name attribute, like this:
<input type="submit" name="submit1" value="Submit 1"/>
<input type="submit" name="submit2" value="Submit 2"/>
<input type="submit" name="submit3" value="Submit 3"/>
The one that is focused is sent along with the form submit, so if you clicked the one with a name of "submit2", that would come through in the form POST (or GET). If enter is hit, the first button in the source (in this case submit1) is considered the default and is sent along. You could set it to display:none to use as a dummy for detecting whether enter was pressed vs actually clicking a submit button.
EDIT:
In response to your comments, to capture the enter key getting pressed in certain elements you can do this with jQuery.
Note, you'll need to give first_name and add_item id attributes, and turn add_item into a type="button" instead of type="submit".
HTML:
<form action="" method="POST">
<input type="text" name="first_name"/>
<input type="text" id="item" name="item"/>
<input type="button" id="add_item" value="Add item"/>
<input type="submit" value="Submit"/>
</form>
JS:
$("#item").keydown(function(event){
if(event.keyCode == 13) {
addFields();
event.preventDefault();
event.stopPropagation();
}
});
$("#add_item").click(function(event) {
addFields();
});
You could set the onclick event on each element you are interested and call a javascript function with a different parameter for each element clicked.
From that function you send the idendifier of the button to the server side as a parameter
Just put a different name on each submit button, whichever one was clicked will be submitted (i.e. its name/value pair) with the form. Forms have worked like this since the begining of (WWW) time.
If the form is sumitted by enter or other keypress, no the first submit button name/value pair will be submitted.
Edit
Re-reading your question, you may want to determine how the form was submitted before it is sent. A click listener on the form can remember the last submit button clicked, but in Firefox, pressing enter in an input dispatches a fake click on the first submit button so you can't detect it.
I think you can't do it reliably other than using the basic method suggested above or Jordan's hidden submit button. If you say why you need to do this, perhaps more help can be provided.
here's an option if you don't mind using jQuery:
example: http://jsfiddle.net/U4Tpw/
use something like
$('form').submit(function() {
// identify the form by getting the id attribute
handleWhichForm($(this).attr('id'));
});

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