Rails AJAX pre-submit form validation

It’s been awhile since a post, but I was on vacation, and then there is the post vacation week of recovery. I don’t have anything big to post, but I figured I’d better post something otherwise I’ll just give up completely on this blog and I don’t want to do that.

So a brief little problem I’ve been working on today is how to do some pre-submit client side validation on a form element in rails if I’m using the remote_form_tag to create my tag. I found a great little solution that was sitting right in front of me the whole time, but it took this article for me to see it. Basically you just use the :before parameter to call your validation script and then just return false if it fails, how great is that. Just another rails solution that ends up being easy as long as you just look at the available tools the right way.

This entry was posted on September 18, 2006 at 7:38 pm and is filed under AJAX, ruby on rails. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

15 Responses to “Rails AJAX pre-submit form validation”

Buffalo Says:
September 28, 2006 at 5:10 pm | Reply
I have been banging my head against this solution all morning, I just cant seem to get it to work.

The following combination of the form_remote_tag, :before, and javascript causes the form to still submit and the action to execute.

Mind to have a look and tell me if I am missing something obvious? I am new to ruby on rails , but relatively adept at javascript, I am hoping I am just doing something blatently wrong .. Thanks! Feel free to email me or I can check back here.

# the form tag
“ValidateForm()”,
:url => { :action => “execute” },
…
) %>

# the javascript
function ValidateForm() {
…
return false
}
Jeff Says:
September 28, 2006 at 7:34 pm | Reply
your code snippet is a little hard to read, just wanted to make sure you are calling :before => “ValidateForm()” and not just , “ValidateForm()”
kellybluebook Says:
October 24, 2006 at 6:13 am | Reply
good site!
hillemania Says:
November 6, 2006 at 4:42 am | Reply
Thanks Kellybluebook, I’m glad some people are reading it and enjoying it.
kori Says:
September 22, 2007 at 8:01 am | Reply
Hope you come back soon!! notem6715
Venkat Says:
February 7, 2008 at 11:06 am | Reply
Hi all, by reading the above comments, I thought that you all might have successfully implemented javascript validation before submitting form to a remote action. But when I tried this with my app, I was left unsuccessful.
Below is the code I have.
```
 {:action => “does”}, :before => “validate_form()”, :update => “update_div” ) %>
input type="text" name="name" id="name"
div updates here
```
In my does.rhtml, I am just displaying some text.

this is my javascript code.
```
function validate_form()
{
var name = document.getElementById(’name’).value;
var errors = “”;
if(name != “kishore”)
{
errors+= “invalid name”;
}
if(errors != “”)
{
alert(errors);
return false;
}
}
```
When I enter the correct data, the text is getting rendered successfuly but when data is entered incorrectly, the alert message gets displayed and the request is still getting processed and the div is getting updated with the text. Where am I missing the obvious thing? Any help appreciated. thanks in advance.
Can mail the stuff if the code here is obscure.

regards,
venkat
Floroskop Says:
March 19, 2008 at 9:08 am | Reply
Hello!
I think this try.
name Says:
September 1, 2008 at 5:36 am | Reply
Good day!,
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Emerson Lackey Says:
July 5, 2010 at 4:04 pm | Reply
I have my own solution for AJAX validations that I think is quite clean and railsey. I actually put together a screencast on the subject – feel free to check it out at:

http://www.emersonlackey.com/article/rails-ajax-validations-jquery
lakshmanan Says:
August 11, 2010 at 12:43 pm | Reply
NOT WORKING…… the request is still getting submitted …
vijaya Says:
October 6, 2010 at 9:46 am | Reply
On using if (! validate_form()) {return false;} the request is still getting processed
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