prevent.default

[jimfog]

I am about to ajaxify a form and my question is where in the context of a form prevent.default is used exaxtly. I know what(in general) prevent.default does but where exactly does it help with form submission.

[dsonesuk]

Where you would use a button, that would on clicking, act as a submit button, but you wish it to perform some other function instead without submitting the form.

[jimfog]

ok...it prevents submitting the form.But can you give me an example where this might be useful.

[davej]

Not only that, but would you use it to prevent a form submission? Or is it better to just change the type="submit" into type="button"?

[justsomeguy]

You would prevent the form from submitting normally and submit it via ajax. If Javascript is disabled then that code never runs and the form submits normally.

[jimfog]

You would prevent the form from submitting normally and submit it via ajax. If Javascript is disabled then that code never runs and the form submits normally.

This is what I had in my mind when I was asking the question.So...in ajax forms we always use prevent.default-for the reasons you mention.

[jeffman]

You will probably need to send data to the server script so it knows whether to respond with a complete document or with data formatted for AJAX. Testing for the value of a hidden form field is usually enough.

[jimfog]

You will probably need to send data to the server script so it knows whether to respond with a complete document or with data formatted for AJAX. Testing for the value of a hidden form field is usually enough.

Ι did not quite understood that.From the moment you send something with AJAX I think it is natural to expect the response in AJAX. Clarify more if you want... Αnd most importantly does form data go with json to the server-this is something I really do not know... Edited May 19, 2013 by jimfog

[jeffman]

I was referring to this:

If Javascript is disabled then that code never runs and the form submits normally.

Depending on your application, you may want to plan for this case.

[jimfog]

I was referring to this:

If Javascript is disabled then that code never runs and the form submits normally.

Depending on your application, you may want to plan for this case.

probably I will not give the option of a fallback to js---it will work only with js

[davej]

probably I will not give the option of a fallback to js---it will work only with js

Then rather than type="submit" you can simply use type="button." I have not used prevent.default with form submission because it seems more straightforward to simply change the type of button when JS initializes. You will probably be changing the hidden field in the form anyway. In many other situations there is no way to avoid the need for prevent.default. For example, what if you don't want a mouse-drag to be allowed to select anything on a page? Edited May 21, 2013 by davej