I know there are plenty of answers surrounding this topic but I just cannot get this to work.
I need to prevent a link button posting back and the following code is not working. The code is definitely being hit in all the required places.
Link button definition:
<asp:LinkButton ID="NavHelp" OnClientClick="showConfirm(event);" OnClick="NavHelp_Click" ToolTip="Help" runat="server"></asp:LinkButton>
Javascript function (definitely being hit)
function showConfirm(event) {
event.stopPropagation();
return false;
}
However after showConfirm returns false the link button still posts back to the server side NavHelp method.
As a side note, I also put a breakpoint in the __doPostback method generated by .NET and it does get hit after showConfirm returns false.
Can anyone shed any light on this?
Right, figured it out. I needed to include the return statement in the OnClientClick attribute:
OnClientClick="return showConfirm(event);"
NOT
OnClientClick="showConfirm(event);"
incidentally, you can use your original code, but rather than using event.stopPropagation() you can use event.preventDefault()
so your code would be
<asp:LinkButton ID="NavHelp" OnClientClick="showConfirm(event);" OnClick="NavHelp_Click" ToolTip="Help" runat="server"></asp:LinkButton>
function showConfirm(event) {
event.preventDefault();
return false;
}
read some more on event.preventDefault() vs event.stopPropagation()
here : http://davidwalsh.name/javascript-events
basically the preventDefault prevents the elemnt from carrying out its dfault action, i.e. visting a link or submitting a form, while stoppropagation allows the dfault action to occur, BUT doesn't inform any parent elements that it has happened.
i created a little jsfiddle : http://jsfiddle.net/XgSXr/ that shows you the prevent default, this should allow you to put in your own javascript logic, display modals etc, before successfully pushing through the link click.
This works:
<asp:LinkButton ID="NavHelp" ClientIDMode="Static" OnClientClick="showConfirm(event);" OnClick="NavHelp_Click" ToolTip="Help" runat="server"></asp:LinkButton>
<script>
$("#NavHelp").click(function(event) {
if (showConfirm()) {
event.stopPropagation();
event.preventDefault();
return false;
}
return true;
});
</script>
Add Return statement in onClientClick Javascript Event
OnClientClick="return showConfirm(event);"
So when showConfirm return false then request will not be transer to server and page not postback.
Related
I have button with both OnClick and OnClientClick events declared.
There is some specific task that I wish to accomplish before the postback occurs but for some strange reason OnClientClick is never fired. I have used it numerous times before and never had this specific issue.
There is something wrong with it, I also tried with adding 'return false' directly to prevent server side processing but postback occurs nevertheless.
I checked whether my form is inside an UpdatePanel but it is not.
<cms:CMSButton ID="btnOk" OnClientClick="clientClick()" OnClick="btnOK_Click" runat="server" ButtonStyle="Default"
EnableViewState="false"></cms:CMSButton>
$(document).ready(function () {
function clientClick() {
console.log("Clicked");
document.getElementById("<%=spinner.ClientID %>").style.display = "block";
document.getElementById("<%= btnOk.ClientID%>").style.display = "none";
}
});
Also I tried firing the event in this manner, with no luck, so there may be something else going on here:
$('#<%=btnOk.ClientID%>').click(function () {
console.log('clicked');
});
Checked the console but could not find any js errors.
As others suggested - avoid document.Ready like the plague.
Now don't take this suggested rule as all or nothing. The simple matter is WHEN you need to use document.ready - then use it, but ALSO when you can avoid using it, don't just out of the blue use it to hook up event code - it REALLY hard to follow.
Now, you posted your markup - I don't know if you left parts out, but again WHEN code is not working, then you want to provide a wee bit more details.
your code should look like this:
<cms:CMSButton ID="btnOk" OnClientClick="clientClick()" OnClick="btnOK_Click"
runat="server" ButtonStyle="Default"
EnableViewState="false"></cms:CMSButton>
<script>
function clientClick() {
console.log("Clicked");
document.getElementById("<%=spinner.ClientID %>").style.display = "block";
document.getElementById("<%= btnOk.ClientID%>").style.display = "none";
}
</script>
So you have a function, you have a onclick, you have a js function wiht that name. Nice, simple code approach here. Be it code behind, or js code in the page? You write a function, and then specify that function. Keep this simple.
In fact, I often suggest that you put the RIGHT below the button so you don't have to go trouging around the page to go find that routine in the markup.
I've seen a few examples on how to do this but they don't seem to be working for me. Having said that, I am doing it a little differently than the examples I've seen so I'm not sure if what I'm trying to do is possible.
I have a multiline asp texbox and onclientclick I want to make sure (among other things) the user hasn't gone over on max length before I submit the onclick event. However, this textbox is part of a user control that will be used X number of times on the page so I can't just grab the control from the Javascript. I have to send the clientID from the code behind. So I'm adding the OnClientClick event on the codebehind and pass the clientID for the control there. I wonder if that's why I'm getting the results I'm getting.
SaveNoteButton.OnClientClick = string.Format("return BeforeSave('{0}');", NoteTextBox.ClientID);
<asp:Button runat="server" CssClass="casenotes-bluebuttons" ID="SaveNoteButton" Text="Save" OnClick="SaveNoteButton_Click" Enabled="false" />
function BeforeSave(noteCtrl) {
var txt = document.getElementById(noteCtrl);
if (txt.value.length > 500) {
alert("false");
return false;
}
else {
alert("true");
return true;
}
}
So in theory, the OnClientClick property is added to the SaveNoteButton button. When it's fired, it passes the NoteTextBox.ClientID, the js checks the textbox length, returns true or false then the OnClick event fires depending on the return value. But it doesn't. I even tried wrapping the method call in an alert and the method is in fact returning what I expect but the OnClick event isn't firing regardless of the method's return value. I even tried removing the method call and hardcoding true and it still doesn't fire. So I know the return value is true and yet no OnClick love.
Oddly enough, it was syntax on the call to the js method.
SaveNoteButton.OnClientClick = string.Format("return BeforeSave('{0}');", NoteTextBox.ClientID);
becomes
SaveNoteButton.OnClientClick = string.Format("BeforeSave('{0}')", NoteTextBox.ClientID);
and it works just fine.
Remove the Enabled="false" bit. This is why the onclick event does not fire.
Alright, this is what I did to solve the problem:
SaveNoteButton.OnClientClick = string.Format("if(!BeforeSave('{0}', '{1}')) return false;", NoteTextBox.ClientID, this._maxLength);
I have this java script validation function that fires when the client clicks btnsave
if the text of the text box is empty then a message box is displayed and the focus is on the
text box but i cannot seem to prevent the page from posting back when the validation fails
AM I missing something. here is my code
function validate()
{
var itemscanned;
itemscanned = document.getElementById('txtItemCode');
if (itemscanned.value == '')
{
alert("Plz Enter Item Code");
return false;
itemscanned.focus
}
else
{
alert(itemscanned.value);
}
}
Write return before function name like this
<asp:Button ID="btnSave" runat="server" Text="Save" CssClass="buttons" OnClientClick="return validate()"/>
If this is an ASP.NET WebForms application, you really should consider using the Validator controls. They handle all of client-side logic you are asking for.
If you are using MVC, there is also a way to do model validation on the client side.
add this if its asp.net button control
OnClientClick = "return validate();"
if it is html button add this
onclick = "return validate();"
Ît belongs how you handle the events. Please show the asp markup and the binding of the javascript event.
You can try to stop event propagation using javascript:
event.stopPropagation();
Read about it here: https://developer.mozilla.org/en-US/docs/DOM/event.stopPropagation
Note: you have to get the event as an parameter to the validate function:
function validate(event) {
var itemscanned;
itemscanned = document.getElementById('txtItemCode');
if (itemscanned.value == '') {
alert("Plz Enter Item Code");
event.stopPropagation();
itemscanned.focus
return false;
}
else
{
alert(itemscanned.value);
}
}
Hope this helps. It's very important how you bind the validate function the button, because asp.net generates a lot of javascript on its own (google for asp.net client validation).
I'm trying to write code that will disable submit button (or all submit buttons) on the page to avoid double postback.
I thought of generating my own postback javascript function (and inject postback javascript using GetPostbackEventReference) but maybe there are some better ways to do this? Or maybe there is some other way to avoid double postbacks?
Update:
I also want to figure out the best place to call javascript, e.g. if I call following script in the onclick button handler then button's server click event won't be wired up.
$('input[type=submit]').attr('disabled', 'disabled')
http://greatwebguy.com/programming/dom/prevent-double-submit-with-jquery/
This should help you
1. $('form').submit(function(){
2. $(':submit', this).click(function() {
3. return false;
4. });
5. });
jQuery:
$('input[type=submit]').attr('disabled', 'disabled')
Otherwise, iterate through all document.getElementByTagName('input')
May be best to do this only for child nodes of the form that was submitted, though?
How about this:
$('input[type=button]').click(function() {
$('input[type=button]').each(function() {
$(this).attr('disabled', 'disabled')
});
});
Anytime any button is clicked, every button on the form becomes disabled.
**Update: I have pasted working code in order to erase any ambiguity about what is going on. I have also tried to remove the preventDefault on both handlers, does not help*
I have a form where upon the button click, a JS event needs to happen, and the form needs to submit.
As per the code below, what I thought would happen is: alert(button), then alert(form), or vice versa. I do not care about sequence.
If i run it however, the alert(button) will show up, but the alert(form) will not.
If i comment out the code for the button, the form alert comes up.
Do i have some fundamental misunderstanding of how this is supposed to work?
jQuery(document).ready(function(){
$("form.example").submit(function(event){
event.preventDefault();
alert("form submitted");
});
$("form.example button").click(function(event){
event.preventDefault();
alert("button clicked");
});
)};
<form class="example" action="/v4test">
<button type="submit">Meow!</button>
</form>
After edit of OP
You do not need to preventDefault of the click.... only the submit... here is you working code:
jsFiddle example
jQuery(document).ready(function(){
$('form.example').submit(function(event){
event.preventDefault();
alert("form submitted");
// stop submission so we don't leave this page
});
$('form.example button').click(function() {
alert("button clicked");
});
});
old answer
You can simply put your .click() and .submit() handlers in series, and they should not cancel out. You have some syntax errors in your pseudo code.... maybe those are causing problems?
Another potential problem is that $("form button") targets the HTML <button> tags. If you use <input type="button" /> you should use $("form:button") and note that <input type="submit" /> is not a button. Anyway, I'll assume you are in fact using the <button> tags.
Usually return false is used inside .submit(function() { ... });. This stops the form from being submited through HTML. s**[topPropagation][6]** is very different. It deals with stopping events "bubbling up" to the parents of elements....... But I don't see how this would effect your case.
If you are doing a true HTML submission, make sure to put your .click() handler first, since a true HTML submission will cause you to leave the page.
If you use return false inside .submit(), the form will not be submitted through the HTML, and you'll have to handle the submission with jQuery / Javascript / AJAX.
Anyway, here is a demonstration of both the .click() and .submit() events firing in series... the code is below:
jsFiddle Example
$(function() {
$('form button').click(function() {
// Do click button stuff here.
});
$('form').submit(function(){
// Do for submission stuff here
// ...
// stop submission so we don't leave this page
// Leave this line out, if you do want to leave
// the page and submit the form, but then the results of your
// click event will probably be hard for the user to see.
return false;
});
});
The above will trigger both handlers with the following HTML:
<button type="submit">Submit</button>
As a note, I suppose you were using pseudo code, but even then, it's much easier to read, and one is sure you're not writing syntax errors, if you use:
$('form').submit(function() { /*submits form*/ });
$('form button').click(function() { /*does some action*/ });
If you put a return false on the click, it should cancel the default behavior. If you want to execute one then the other, call $('form').submit() within the click function. e.g.
$('form').submit { //submits form}
$('form button').click {
// does some action
$('form').submit();
}
There seems to be a bit of confusion about propagation here. Event propagation (which can be disabled by stopPropagation) means that events "bubble up" to parent elements; in this case, the click event would register on the form, because it is a parent of the submit button. But of course the submit handler on the form will not catch the click event.
What you are interested in is the default action, which in the case of clicking a submit button is to submit the form. The default action can be prevented by either calling preventDefault or returning false. You are probably doing the latter.
Note that in Javascript functions which do not end with an explicit return do still return a value, which is the result of the last command in the function. You should end your click handler with return; or return true;. I have no idea where I got that from. Javascript functions actually return undefined when there is no explicit return statement.
Does clicking the button submit the form? If so:
// Disable the submit action
$("form").submit(function(){
return false;
});
$("form button").click(function(){
// Do some action here
$("form").unbind("submit").submit();
});
If you don't unbind the submit event when you click the button, the submit will just do nothing.