# New to RoR - working through book have some questions **URL:** \ **Category:** Rails\ **Created:** [September 19, 2009, 11:57pm UTC](https://www.ruby-forum.com/t/new-to-ror-working-through-book-have-some-questions/175796 "2009-09-19T23:57:09Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![andrew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/f19dbf/32.png) [@andrew](https://www.ruby-forum.com/u/andrew)\ **Post date:** [September 19, 2009, 11:57pm UTC](https://www.ruby-forum.com/t/new-to-ror-working-through-book-have-some-questions/175796/1 "2009-09-19T23:57:09Z")
Greetings, I’m new to Ruby on Rails. I’m working through “Agile Web D. with Rails 3rd Edition” and it is going quite well. However, there are times I don’t quite understand _why_ I’m doing something. For some items, I think I understand, but I would like some confirmation. So, I’m going to post my questions here and I hope that someone can help me in understanding. In Chapter 9, I’m working on creating an AJAX-based shopping cart. So, I’m replacing this: \<%= button\_to “Add to Cart”, :action =\> ‘add\_to\_cart’, :id =\> product %\> With this: \<% form\_remote\_tag :url =\> { :action =\> ‘add\_to\_cart’, :id =\> product } do %\> \<%= submit\_tag “Add to Cart” %\> \<% end %\> Questions on this: I can explain that the first second is doing this: “Use ruby helper button\_to to add a button for each item, and it calls the action add\_to\_cart, passing back the product that was selected” I can’t seem to be able to explain the second section. “The rails helper form\_remote\_tag is called, which is similar to a method call and the :url is similar to passing a parameter to a method. The items between { and } are the values for the :url parameter.” Correct? What is the “submit\_tag”? Is that similar to the input type=“submit” in HTML? Is it basically saying, show a button? Why is the do%\> and \<% end %\> part needed? Is this saying do the following ruby code? The difference between the two seconds, as the book explains, is that the second sends an AJAX request instead of a POST request. I read that, I think I understand it, but I don’t exactly know why there is a difference. Can someone explain? I’ll just start with this. Thanks, Andrew ---
**Author:** ![andrew](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/f19dbf/32.png) [@andrew](https://www.ruby-forum.com/u/andrew)\ **Post date:** [September 20, 2009, 12:03am UTC](https://www.ruby-forum.com/t/new-to-ror-working-through-book-have-some-questions/175796/2 "2009-09-20T00:03:00Z")
On Sep 19, 8:40 pm, andrew [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > \<% form\_remote\_tag :url =\> { :action =\> ‘add\_to\_cart’, :id =\> > I can’t seem to be able to explain the second section. “The rails > helper form\_remote\_tag is called, which is similar to a method call > and the :url is similar to passing a parameter to a method. The > items between { and } are the values for the :url parameter.” > Correct? pretty much. What’s in the :url hash are routing options, ie the same thing as the second parameter to button\_to or link\_to > What is the “submit\_tag”? Is that similar to the input type=“submit” > in HTML? Is it basically saying, show a button? the xxx\_tag helpers generate the appropriate input tags, so submit tag is input type=submit, textfield\_tag is a textfield etc. > Why is the do%\> and \<% end %\> part needed? Is this saying do the > following ruby code? form\_tag / remote\_form\_tag take a block - the do/end are just the block delimiters > The difference between the two seconds, as the book explains, is that > the second sends an AJAX request instead of a POST request. I read > that, I think I understand it, but I don’t exactly know why there is a > difference. Can someone explain? AJAX is a big topic in itself but the key difference is that whereas a ‘normal’ request reloads the whole page, an AJAX request just happens in the background and you get to decide how the response from the server is used. Fred