In the following page, with Firefox the remove button submits the form, but the add button does not.
How do I prevent the remove button from submitting the form?
function addItem() {
var v = $('form :hidden:last').attr('name');
var n = /(.*)input/.exec(v);
var newPrefix;
if (n[1].length == 0) {
newPrefix = '1';
} else {
newPrefix = parseInt(n[1]) + 1;
}
var oldElem = $('form tr:last');
var newElem = oldElem.clone(true);
var lastHidden = $('form :hidden:last');
lastHidden.val(newPrefix);
var pat = '=\"' + n[1] + 'input';
newElem.html(newElem.html().replace(new RegExp(pat, 'g'), '=\"' + newPrefix + 'input'));
newElem.appendTo('table');
$('form :hidden:last').val('');
}
function removeItem() {
var rows = $('form tr');
if (rows.length > 2) {
rows[rows.length - 1].html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<html>
<body>
<form autocomplete="off" method="post" action="">
<p>Title:<input type="text" /></p>
<button onclick="addItem(); return false;">Add Item</button>
<button onclick="removeItem(); return false;">Remove Last Item</button>
<table>
<th>Name</th>
<tr>
<td><input type="text" id="input1" name="input1" /></td>
<td><input type="hidden" id="input2" name="input2" /></td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
</body>
</html>
You're using an HTML5 button element. Remember the reason is this button has a default behavior of submit, as stated in the W3 specification as seen here:
W3C HTML5 Button
So you need to specify its type explicitly:
<button type="button">Button</button>
in order to override the default submit type. I just want to point out the reason why this happens.
Set the type on your buttons:
<button type="button" onclick="addItem(); return false;">Add Item</button>
<button type="button" onclick="removeItem(); return false;">Remove Last Item</button>
...that'll keep them from triggering a submit action when an exception occurs in the event handler. Then, fix your removeItem() function so that it doesn't trigger an exception:
function removeItem() {
var rows = $('form tr');
if ( rows.length > 2 ) {
// change: work on filtered jQuery object
rows.filter(":last").html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
Note the change: your original code extracted a HTML element from the jQuery set, and then tried to call a jQuery method on it - this threw an exception, resulting in the default behavior for the button.
FWIW, there's another way you could go with this... Wire up your event handlers using jQuery, and use the preventDefault() method on jQuery's event object to cancel the default behavior up-front:
$(function() // execute once the DOM has loaded
{
// wire up Add Item button click event
$("#AddItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of add logic
});
// wire up Remove Last Item button click event
$("RemoveLastItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of remove last logic
});
});
...
<button type="button" id="AddItem" name="AddItem">Add Item</button>
<button type="button" id="RemoveLastItem" name="RemoveLastItem">Remove Last Item</button>
This technique keeps all of your logic in one place, making it easier to debug... it also allows you to implement a fall-back by changing the type on the buttons back to submit and handling the event server-side - this is known as unobtrusive JavaScript.
Sometime ago I needed something very similar... and I got it.
So what I put here is how I do the tricks to have a form able to be submitted by JavaScript without any validating and execute validation only when the user presses a button (typically a send button).
For the example I will use a minimal form, only with two fields and a submit button.
Remember what is wanted:
From JavaScript it must be able to be submitted without any checking. However, if the user presses such a button, the validation must be done and form sent only if pass the validation.
Normally all would start from something near this (I removed all extra stuff not important):
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="submit" value="Send" onclick="JavaScript:return Validator();" />
</form>
See how form tag has no onsubmit="..." (remember it was a condition not to have it).
The problem is that the form is always submitted, no matter if onclick returns true or false.
If I change type="submit" for type="button", it seems to work but does not. It never sends the form, but that can be done easily.
So finally I used this:
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="button" value="Send" onclick="JavaScript:return Validator();" />
</form>
And on function Validator, where return True; is, I also add a JavaScript submit sentence, something similar to this:
function Validator(){
// ...bla bla bla... the checks
if( ){
document.getElementById('theFormID').submit();
return(true);
}else{
return(false);
}
}
The id="" is just for JavaScript getElementById, the name="" is just for it to appear on POST data.
On such way it works as I need.
I put this just for people that need no onsubmit function on the form, but make some validation when a button is press by user.
Why I need no onsubmit on form tag? Easy, on other JavaScript parts I need to perform a submit but I do not want there to be any validation.
The reason: If user is the one that performs the submit I want and need the validation to be done, but if it is JavaScript sometimes I need to perform the submit while such validations would avoid it.
It may sounds strange, but not when thinking for example: on a Login ... with some restrictions... like not allow to be used PHP sessions and neither cookies are allowed!
So any link must be converted to such form submit, so the login data is not lost.
When no login is yet done, it must also work. So no validation must be performed on links.
But I want to present a message to the user if the user has not entered both fields, user and pass. So if one is missing, the form must not be sent! there is the problem.
See the problem: the form must not be sent when one field is empty only if the user has pressed a button, if it is a JavaScript code it must be able to be sent.
If I do the work on onsubmit on the form tag, I would need to know if it is the user or other JavaScript. Since no parameters can be passed, it is not possible directly, so some people add a variable to tell if validation must be done or not. First thing on validation function is to check that variable value, etc... Too complicated and code does not say what is really wanted.
So the solution is not to have onsubmit on the form tag. Insead put it where it really is needed, on the button.
For the other side, why put onsubmit code since conceptually I do not want onsubmit validation. I really want button validation.
Not only the code is more clear, it is where it must be. Just remember this:
- I do not want JavaScript to validate the form (that must be always done by PHP on the server side)
- I want to show to the user a message telling all fields must not be empty, that needs JavaScript (client side)
So why some people (think or tell me) it must be done on an onsumbit validation? No, conceptually I am not doing a onsumbit validating at client side. I am just doing something on a button get pressed, so why not just let that to be implemented?
Well that code and style does the trick perfectly. On any JavaScript that I need to send the form I just put:
document.getElementById('theFormID').action='./GoToThisPage.php'; // Where to go
document.getElementById('theFormID').submit(); // Send POST data and go there
And that skips validation when I do not need it. It just sends the form and loads a different page, etc.
But if the user clicks the submit button (aka type="button" not type="submit") the validation is done before letting the form be submitted and if not valid not sent.
Well hope this helps others not to try long and complicated code. Just not use onsubmit if not needed, and use onclick. But just remember to change type="submit" to type="button" and please do not forget to do the submit() by JavaScript.
I agree with Shog9, though I might instead use:
<input type = "button" onClick="addItem(); return false;" value="Add Item" />
According to w3schools, the <button> tag has different behavior on different browsers.
You can simply get the reference of your buttons using jQuery, and prevent its propagation like below:
$(document).ready(function () {
$('#BUTTON_ID').click(function(e) {
e.preventDefault();
e.stopPropagation();
e.stopImmediatePropagation();
return false;
});});
$("form").submit(function () { return false; });
that will prevent the button from submitting or you can just change the button type to "button" <input type="button"/> instead of <input type="submit"/>
Which will only work if this button isn't the only button in this form.
Suppose your HTML form has id="form_id"
<form id="form_id">
<!--your HTML code-->
</form>
Add this jQuery snippet to your code to see result,
$("#form_id").submit(function(){
return false;
});
Buttons like <button>Click to do something</button> are submit buttons.
You must add type
This is an html5 error like has been said, you can still have the button as a submit (if you want to cover both javascript and non javascript users) using it like:
<button type="submit" onclick="return false"> Register </button>
This way you will cancel the submit but still do whatever you are doing in jquery or javascript function`s and do the submit for users who dont have javascript.
Just add e.preventDefault(); in your method should prevent your page from submitting forms.
function myFunc(e){
e.preventDefault();
}
According to the MDN Web Docs
The preventDefault () method of the Event interface tells the user
agent that if the event is not explicitly processed, its default
action should not be taken into account as it would normally be. The
event continues to propagate as usual, unless one of its listeners
calls stopPropagation () or stopImmediatePropagation (), either of
which terminates the propagation.
The return false prevents the default behavior. but the return false breaks the bubbling of additional click events. This means if there are any other click bindings after this function gets called, those others do not Consider.
<button id="btnSubmit" type="button">PostData</button>
<Script> $("#btnSubmit").click(function(){
// do stuff
return false;
}); </Script>
Or simply you can put like this
<button type="submit" onclick="return false"> PostData</button>
I am sure that on FF the
removeItem
function encounter a JavaScript error, this not happend on IE
When javascript error appear the "return false" code won't run, making the page to postback
Set your button in normal way and use event.preventDefault like..
<button onclick="myFunc(e)"> Remove </button>
...
...
In function...
function myFunc(e){
e.preventDefault();
}
return false;
You can return false at the end of the function or after the function call.
Just as long as it's the last thing that happens, the form will not submit.
if you have <input />
use it
<input type="button"/>
if you have <button>btn</button>
use it
<button type="button">btn</button>
Here's a simple approach:
$('.mybutton').click(function(){
/* Perform some button action ... */
alert("I don't like it when you press my button!");
/* Then, the most important part ... */
return false;
});
I'm not able to test this right now, but I would think you could use jQuery's preventDefault method.
The following sample code show you how to prevent button click from submitting form.
You may try my sample code:
<form autocomplete="off" method="post" action="">
<p>Title:
<input type="text" />
</p>
<input type="button" onclick="addItem()" value="Add Item">
<input type="button" onclick="removeItem()" value="Remove Last Item">
<table>
<th>Name</th>
<tr>
<td>
<input type="text" id="input1" name="input1" />
</td>
<td>
<input type="hidden" id="input2" name="input2" />
</td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
<script language="javascript">
function addItem() {
return false;
}
function removeItem() {
return false;
}
</script>
The function removeItem actually contains an error, which makes the form button do it's default behaviour (submitting the form). The javascript error console will usually give a pointer in this case.
Check out the function removeItem in the javascript part:
The line:
rows[rows.length-1].html('');
doesn't work. Try this instead:
rows.eq(rows.length-1).html('');
https://developer.mozilla.org/pt-BR/docs/Web/API/HTMLFormElement/submit_event
Do your logic on the form onsubmit event
submitter Read only
An HTMLElement object which identifies the button or other element which was invoked to trigger the form being submitted.
onsubmit="(evt) => console.log(evt)"
The event itself will bring along the caller and some usefull info.
Just use evt.preventDefault(); (default submit) evt.stopPropagation(); (submit bubbling) if the caller is a
So I have a form that when submitted requires confirmation. I am using Javascript confirm to prompt for this. However, I do not want it to refresh if someone hits cancel. I thought putting an empty else statement would do so, however it appears I was wrong.
Not sure what I need to be doing to make sure it does NOT refresh if someone presses cancel on the popup.
the JS confirm code
function postConfirm() {
if (confirm('You will not have another chance after submitting to view your post. Please make sure it is exactly how you want it before continuing. ')) {
yourformelement.submit();
} else {
}
}
the form that uses this JS function (if needed)
<div id="uploadForm">
<center>
<form enctype="multipart/form-data" action="functions/post_upload.php" method="post">
<input type="hidden" name="MAX_FILE_SIZE" value="99999999" />
<div><textarea id="text" cols="70" rows="15" name="entry"></textarea></div>
<p> Attach an image to this memory!</p>
<input name="userfile" type="file"><br>
<input type="submit" value="Submit" class="blueButton" onclick="postConfirm()"/></div>
</form></center>
</div>
Change:
onclick="postConfirm()"
to
onclick="return postConfirm()"
and in your function, make the else:
else {
return false;
}
jsFiddle example
try adding
return false;
to the else part of your if statement.
Edit:
Also modify your call to the function so that the return false is passed back to the submit action (which is fired when the button is clicked).
<input type="submit" value="Submit" class="blueButton" onclick="return postConfirm()"/></div>
You can prevent form submission using the preventDefault() method of event object and manually submit the form upon confirmation using the submit() method of form elements.
Change your HTML to:
<input type="submit" value="Submit" class="blueButton" onclick="postConfirm(event)"/></div>
function postConfirm(e) {
e.preventDefault();
if(confirm('You will not have another chance after submitting to view your post. Please make sure it is exactly how you want it before continuing. '))
yourformelement.submit();
}
However, it is better to avoid inline javascript since it is considered a bad practice. Instead you can do:
var button = document.getElementsByClassName("blueButton")[0];
button.addEventListener("click",function(e) {
e.preventDefault();
if(confirm('You will not have another chance after submitting to view your post. Please make sure it is exactly how you want it before continuing. '))
yourformelement.submit();
});
try
<input type="button" value="Submit" class="blueButton" onclick="postConfirm()"/></div>
instead of
<input type="submit" value="Submit" class="blueButton" onclick="postConfirm()"/></div>
HI All
I have following lines in my JSP.
<s:submit name="submit" onclick="return validateUser();" action="saveUser" theme="simple" value="Save" />
The java script method validateUser(), validates the user and returns true or false. The form should not be submitted when the validation fails.
This is working in the FF but not in the IE8.
IE8 submits the form even after validation fails.
Never assume you can cancel the submit button, instead set some javascript variable or hidden field on the form and use onsubmit. Take my word for it. Have the onsubmit look at the variable set by the different submit buttons
Never use javascript: (javascript colon) unless you are in IE and have a VBScript as the first script on the page. In all other cases javascript is default.
Never use such atrocities as <a href="javascript:something()" instead of <a href="#" onclick="return something()
Lastly, in IE, when you have an error occurring, the default action is to submit the form. You may very well have other errors completely elsewhere and have the validate return the error, which is seen as true (0 evaluates to false, most anything else is true)
<script type="text/javascript">
var isvalidateNeeded = true;
function validate(theForm) {
if (!isvalidateNeeded) return true; // allow submission
. // normal validation
.
.
return true; // allow submission
}
</script>
<form onsubmit="return validate(this)">
.
.
.
<input type="submit" name="subaction" value="Test" onclick="isvalidateNeeded=false" />
<input type="submit" name="subaction" value="Check" onclick="isvalidateNeeded=false" />
<input type="submit" name="subaction" value="Submit" onclick="isvalidateNeeded=true" />
</form>
First, a single form that can perform multiple actions is a bad idea, that said...
Do not use submit buttons, instead:
<button type="button" onclick="javascript:validateUser();">Save user</button>
<button type="button" onclick="javascript:deleteUser();">Delete user</button>
Now you only have to worry about default submit behaviour of a form (when user presses enter in a field).
Only thing you need to change is in your validateUser() function.
IE is looking for the return value on the event, so you need to specify this:
event.returnValue = true;
return true;
event.returnValue = false;
return false;
Please note that if there is a bug or error in validateUser() or deleteUser() then "return false" will NOT stop the anchor action and your browser will try to link to the href "subaction". Here is the logic:
User clicks on anchor
onClick fires validateUser()
There is an error in validateUser() so Javascript crashes and stops all code execution.
return false is never fired because Javascript has already stopped.
browser tries to go to href attribute
If you are relying on a third party JavaScript API (I was using code supplied by Recyclebank to spawn a popup), and the third party API makes an update that breaks the JavaScript, then you'll have problems.
The following will stop the link under normal conditions and error conditions.
<a class="button" href="javascript:;" onclick="validateUser();return false;">Validate User</a>
I have written following function which checks whether start_date field is not empty and displays proper message when submit button is clicked. But then it takes the control to the previous page. So user has to write again all other fields on that form.
Is there any way to stay on that page even after prompting the error message, with all other fields value.
//JavaScript
function checkform() {
if(document.frmMr.start_date.value == "") {
alert("please enter start_date");
return false;
} else {
document.frmMr.submit();
}
}
// HTML
<html>
<form name=frmMr action="page1.jsp">
Enter Start date:
<input type="text" size="15" name="start_date" id="start_date">
<input type="submit" name="continue" value="submit" onClick="checkform();">
</form>
</html>
Thanks in advance
While you have a return value in checkform, it isn't being used anywhere - try using onclick="return checkform()" instead.
You may want to considering replacing this method with onsubmit="return checkform()" in the form tag instead, though both will work for clicking the button.
You can simply make the start_date required using
<input type="submit" value="Submit" required />
You don't even need the checkform() then.
Thanks
use return before calling the function, while you click the submit button, two events(form posting as you used submit button and function call for onclick) will happen, to prevent form posting you have to return false, you have did it, also you have to specify the return i.e, to expect a value from the function,
this is a code:
input type="submit" name="continue" value="submit" onClick="**return** checkform();"
Don't know for sure, but it sounds like it is still submitting. I quick solution would be to change your (guessing at your code here):
<input type="submit" value="Submit" onclick="checkform()">
to a button:
<input type="button" value="Submit" onclick="checkform()">
That way your form still gets submitted (from the else part of your checkform()) and it shouldn't be reloading the page.
There are other, perhaps better, ways of handling it but this works in the mean time.
I'm working on a script where all I want it to do (right now) is redirect the user based on which button they press. Eventually it will take form input and incorporate that into the redirect, but right now I'm just trying to get the buttons to send the user off to the appropriate site. However, My redirects aren't working.
<html>
<head>
<title>
Home
</title>
</head>
<body>
<script type="text/javascript">
<!--
var textstring;
var btnWhichButton;
//Gets the text from the form
function getQ() {
textstring = document.forms['Search'].elements[0].value;
}
//Does a Google Search
function googleSearch() {
window.location ="http://www.google.com";
}
//Does a YouTube Search
function youtubeSearch() {
window.location = "http://youtube.com";
}
//Figure out which button was pressed
function whichButton() {
if (btnWhichButton.value == 'Google Search' ) {
googleSearch();
} else if (btnWhichButton.value == 'YouTube Search' ){
youtubeSearch();
}
}
//main function to run everything
function main() {
getQ();
whichButton();
}
// -->
</script>
<form name="Search" >
<input type="text" name="q" size="31" maxlength="255" value="" />
<input type="submit" value="Google Search" onclick="btnWhichButton=this; main();" />
<input type="submit" value="YouTube Search" onclick="btnWhichButton=this; main();" />
</form>
</body>
</html>
When either button is clicked, the page just reloads with ?q= appended to the url, it doesn't redirect. Any help?
You want to use a button not an input type='submit'. Your current buttons are submitting the form, not performing their onclick actions.
Or block the submit action in some way. Or you could use your functions to set the form action to the url and just let it submit.
Your scripts seem highly overcomplicated. Why not have three functions: getQ, googleSearch, and youTubeSearch? Then inside the onClick event you can call the exact function, including this.value inside the input parameters and calling getQ from inside that function? Your method seems highly inefficient. If you're going to have separate functions for each of them anyways, there's no use in going through two other functions in order to get to them.
A submit button will always submit the form without a return false at the end of the onClick event, and since the default posting method is GET, its attaching ?q= to the end of your URL because that field is blank and it's the only input field in the form.
For redirecting to new page you no need to use the big javascript function.
<html> <body>
<input type="button" value="Google Search" onclick="javascript:window.location.href='http://www.google.com'" />
<input type="button" value="You tube Search" onclick="javascript:window.location.href='http://youtube.com'" />
</body></html>
Please check whether it helps you.
Well as jasonbar says, change your input to be of type 'button' and not 'submit'. Plus, I'd rather use window.location.href instead of window.location only. I don't know possible this is good practice...happy programming.