I've been told you need to add a "return false;" to the end of a method that submits the form.
I've tried the following code, and it appears though I omit the "return false" the form gets submitted only once, not twice. Does anyone know the standard browser behavior that dictates whether the javascript form submission overrides the html form submission or are they considered one action?
<form name="myform" action="">
<button type='submit' onclick='submitForm();'>Submit</button>
</form>
<script>
function submitForm(){
console.log('Button Clicked');
document.myform.submit();
}
</script>
if I change the button to be an input type, I also get only one submission not two, from my tests, but I want to confirm this is the standard behavior.
i.e.:
<input type='submit' onclick='submitForm();'/>
As stated in the comments of the answer you linked, the fact is that submit will only submit the data in the form you handled, while the onclick attribute will trigger your method call, which triggers inside it another submit.
I think it acts as follow (feel free to correct me if I am wrong):
You click on your button.
Clicking triggered the onclick value, which will call your submitForm() method.
Your method prints 'Button Clicked' in the console.
Your document is sent a first time.
Form is submitted a second time through its submit type.
That would explain why you see your console.log a single time. You would have to trace the result in your server-side in order to check if the document has been submitted once or twice.
(And if it is once, this answer is utterly wrong.)
Related
So I tried a couple of things when I using JS and try submitting inputs, and there are odd things I didn't understand the logic.
There is a difference between <input tpye="submit/> inside and outside of <form> tag. If it's inside the form tag I need to use preventDefault() function, but if it's outside form tag I am not required to do that if write simple js vanilla code.
Why is that?
What the difference between onsubmit and onclick ? especially in a form tag. Because If I use onsubmit the js code doesn't really work.
If I use preventDefault(event) it's preventing from the form to be sended into a server, and instead it doing the calculations with the browser only ?
Thanks !
By default, if you have an input of type "submit" in a form then clicking that input (or hitting enter after filling in ANY inputs in the form) will send a post or get request to the server, redirecting the current page to the server's response.
This was the original way to submit form data to a server, without using javascript. If you want to prevent this from happening, you can either replace the submit input with a plain button (<button onclick="doSomething()">Submit</button>), or prevent the default submission event: (form.onsubmit = event => event.preventDefault()).
The difference between onsubmit and onclick is that onsubmit only fires when a submission event is emitted from the form. To emit a submit event, the form needs an <input type="submit"> to be clicked, or for the user to trigger a submission by hitting enter.
Another way to prevent this default behavior is to return false in the submission handler.
onclick only gets fired when an element is clicked. Because events in javascript propagate up to parents, this will also trigger any onclick handlers on all parent elements.
If you want to completely ignore the default form submission behavior, then you can define a button with an onclick handler to handle your custom submission logic.
If you have a type="submit" input (Note, The default value for the type attribute of button elements is "submit") inside a form, the default action on click is to submit that form. To prevent it from submitting, place the button outside the </form>. This works because the button doesn't refer to any form to submit. You can instead, add a listener and call event.preventDefault(). This works because you are telling the browser NOT to take the default action (submitting the form)
onsubmit is used mostly on <form> elements. It triggers right before the form is submitted regardless of how it is submitted. onclick can be emitted from just about any element. It occurs when you click on an element. This could be on an <input>, a <button>. or even an entire <form>
Don't use this.
This may be too short and sweet, but this is all I have to ask. When I have two buttons in HTML, I use one button for form submission, and another to trigger a javascript event. However, what is happening is that both buttons perform form submits. I want to use the other button for submits without making it unusable by javascript. WHat are the possible methods I can do this?
To expand on what Saravanan Sachi and aladin8848 already said:
If you are using <input> for your buttons, type="submit" will always submit your form and type="button" will be a plain, non-form submitting button.
If though you are using <button></button> tags for your buttons (as I tend to do), they have a 'default' type of submit, so you have to explicitly set their type to button ex. <button type="button">Do JS click things</button> to prevent it from submitting your form.
Use
<input type="submit">
to submit the form and
<input type="button">
to call JavaScript method
Use
<input type='button' onclick='....'>
instead of what you are probably using
<input type='submit'>
you can do the next:
var buttonList = document.getElelmentsByTagName('button');
buttonList[2].addEventListener('click', function(event){
event.preventDefault();
this.removeEventListener("click", this, false);
//do something, like add your own event
});
you should be more specific getting the buttons, and i don't test the code, but the idea is that, remove events and default behaviour of the second button.
i hope this helps you.
I made a form and set its attr to onsubmit="return false"
Now I need to execute some actions before the actual submit like this:
$('input[name=submit]').click(function(){
$('.switch-input').attr('checked','checked');//getting all values of chbz
//here goes a little more code//
$('form[name=setform]').removeAttr('onsubmit');//finally sending to $_POST
});
At first glance everything works correct, but I wonder will it 100% execute all code before sending or did I do it wrong?
The onsubmit="return false" attribute will prevent the form from being submitted as it normally would be. However, when the user clicks the Submit input, the above snippet will execute once, removing the onsubmit attribute and making the form able to be submitted normally, but the user will have to click Submit again to submit it.
You can keep the existing snippet and tell jQuery to submit the form explicitly, via the third variation of the .submit() method:
$('input[name=submit]').click(function(){
$('.switch-input').attr('checked','checked');//getting all values of chbz
//here goes a little more code//
$('form[name=setform]').removeAttr('onsubmit');//make the form submittable
$('form[name=setform]').submit();//finally sending to $_POST
});
Alternatively, you can remove the onsubmit="return false" attribute, and use the .submit(handler) variation of the method, which simplifies your code and guarantees the handler will execute just before the form is submitted:
$('form[name=setform]').submit(function(){
$('.switch-input').attr('checked','checked');//getting all values of chbz
//here goes a little more code//
});
You could consider dismissing the onsubmit attribute and instead use your .click() code and just put return false at the end. You could also use .submit() as suggested by Stiliyan.
There is a PHP-generated HTML 4 transitional page that is used to edit data from a database of a single record. The user has two options: to store changes or delete the record. I use a form with controls (some of them are hidden):
<form method="post" action="object_mod.php"><!-- this is another file -->
<!-- inputs follow -->
As I want to process two actions ie. delete or save a record I put two submit buttons on the form, before </FORM> tag:
<input type="submit" id="btnSubmit" value="Save">
<input type="submit" id="btnDelete" value="Delete">
</form>
Because the user should confirm deletion I added the following onclick event:
<input type="submit" id="btnDelete" value="Delete" onclick="javascript:deleteRecordConfirm();">
(I also tried without javascript: and onclick="javascript:deleteRecordConfirm(); return true;"), but it doesn't submit a form.
The JS function is
function deleteRecordConfirm(){
if(confirm('Are you sure to delete?')){
document.getElementById("field_action").value=-1;
//document.forms[0].submit();
return true;
}
}
This field_action is set to -1 so I know in object_mod.php that I want to delete record rather than save it.
Here go question, why this form doesn't submit on deletion?
I think it would be good if a user has Javascript disabled to submit a form anyway, even without confirmation so that is why I use <INPUT TYPE="submit"> for deletion. Is it a good idea? I was thinking about giving two independent forms (in fact deletion should have only one hidden field with record id) with their own submit buttons, one for deletion and the other for saving.
In fact the page will work in some kind of intranet, with users who I trust and I'm not afraid of hacking or something, but any security remarks are also welcome.
(I tested it on Firefox 19.0 and Javascript console shows no errors, w3c validator says it's a valid page).
The form should submit according to your code. The only thing I spot is that you should terminate the input tags with />.
BUT... this way, even if the the confirm is cancelled, the form will be submitted. Use the form.onsubmit handler and if that returns false, the form will not submit.
I dont think #B3aT's answer is right in that not unconditionally the best way to "externalise" so to say. Many the the simplest is the best.
I think the best way is to "externalize" the actual form posting.
//make regular buttons (not submit)
//call your own functions (save and delete)
//after you have done your logic do document.forms["myform"].submit();
Another solution is to add a checkbox named "delete" and rename the "save" button to "Done or do". And on server side, if "delete" is activated, then ..delete it.
Usually the "delete" is required "per entry" level (same user have multiple records), so you will have to make a separate button/link and eventually do an ajax request/access an URL with ?delete=1&id=3.
You need to make custom yes/no windows or use a jQuery plugin for it, the only browser standard is "confirm".
OK, it worked, and this was in fact very stupid mistake. The problem was with this button as it was outside the form. I was so sure that I have it inside that I did not review PHP code but copied all from script not the HTML output as I should have done.
As I understand this correctly the line document.forms[0].submit(); worked but it was not because it was button who submitted the form but document.form[0] object itself.
Thank you for all your answers. I will try this form.onsubmit hint from Marcell.
I want to have a form on the main section of my webpage with buttons along the bottom of this section to submit it.
I also want to have a side bar with links to other pages, but make it so that whenever a link is clicked it acts as a button to submit the form too. (ie in the HTML, the code for these links will be outside of the form tags, but I would like them to still act as buttons for the form)
Is this possible?
You can solve this very easy without JavaScript in HTML5:
<input type="submit" form="id_of_the_form" value="Submit">
<form id="id_of_the_form" action method></form>
And you can style those buttons as you like. As in the example, the button can be placed at any point within the dom - no need to put it into the form.
Use the following onclick handler in your link, replacing formId with the ID for the form you want to submit...
onclick="document.getElementById('formId').submit();return false;"
Update
As #Juan (and others, especially #JoeTaylor) have mentioned, the above will not fire any client-side validation code associated with the form. The easiest way that I'm aware of to make it do so is to fire the click event of a submit button within the form. For instance, this could be used on your link...
onclick="document.getElementById('formSubmitButton').click();return false;"
Although you don't mention anything to do with server-side processing, I will take the assumption that is the point of your form. One additional thing I would say on the back of this is that you should ALWAYS replicate the validation back on the server. JavaScript is very easy to bypass, and so you should make sure the values reaching your server are correct, and never assume the JavaScript has done it's job.
The easiest way to ensure your form is submitted and validated by whatever function you've attached is not to call the form's submit() method, but to call its submit button's click() method instead.
Consider the following form:
<form id="bar" method="post" action="/echo/html/">
<input type="text" id="foo" name="foo">
<input type="submit" value="Submit">
</form>
Right now, clicking submit doesn't do anything special. But what if you wanted to ensure the text input had a value before sending anything off to the server? You might accomplish that as follows:
function validateBarForm() {
var txt = this.querySelector("input[type=text]");
if (txt.value == "") {
txt.style.outline = "solid red 2px";
return false;
}
}
document.getElementById("bar").onsubmit = validateBarForm;
Now if you click submit the form won't be submitted with a blank text input. But what if you submit the form programmatically? Let's add a link first...
submit form
Note that this link is outside of the form tag. We can trivially attach a submission function:
function submitBarForm() {
document.getElementById("bar").submit();
}
document.getElementById("submit-bar").onclick = submitBarForm;
We click "submit form" and... Whoops! The validation function is not performed! There are a few ways to skirt this issue, but my favourite is to simply have JavaScript simulate a click to the submit button. I find this holds up to changes a lot better than hardcoding a call to the validation function.
function submitBarForm() {
document.querySelector("#bar input[type=submit]").click();
}
Now when you click the link, the form is validated, and if everything checks out it's submitted too. But don't take my word for it--head on over to jsfiddle.net and see for yourself.
By adding an onclick javascript function to your form.
document.forms["myform"].submit();
Where "myform" is the id of your form. Here's a nice walkthrough: http://www.javascript-coder.com/javascript-form/javascript-form-submit.phtml
For example, the button might be:
<button onclick="document.forms['myform'].submit();">Hi</button>
Yes the button's click event add document.getElementById('formId').submit();
<form name="myform" action="action.php">
// Your form
</form>
Submit form
Or you can use jQuery:
<form name="myform" action="action.php">
// Your form
</form>
Your text
I do this myself with hidden submit buttons in the actual form, and outside of the form - anywhere else on the page - labels that reference the submit button and fire it.
In the form:
<input type='submit' id='hiddenSubmit'>
And anywhere else:
<label for='hiddenSubmit'>click me!</label>
Seems to do the job.