# Ajax partial need unique ids? **URL:** \ **Category:** Rails\ **Created:** [January 26, 2009, 2:44am UTC](https://www.ruby-forum.com/t/ajax-partial-need-unique-ids/158628 "2009-01-26T02:44:01Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![david](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/aeb1de/32.png) [@david](https://www.ruby-forum.com/u/david)\ **Post date:** [January 26, 2009, 2:44am UTC](https://www.ruby-forum.com/t/ajax-partial-need-unique-ids/158628/1 "2009-01-26T02:44:01Z")
Im not sure about the best way to go about dealing with the following situation. I have a number of popups that each contain a link “add time” which ajaxes and renders a partial: page.replace\_html “add\_appt\_#{params[:day]}”, :partial =\> ‘add\_appt’ and within this partial a javascript function is called which populates an element with id “start\_time”. The problem that I am facing is that if I click and close the partial without replacing the new partial, the javascript function finds the first element in the DOM with id “start\_time” and it doesnt work. My question is would it be better to rename all the start\_time elements so that they are all unique? or would it be better to somehow replace the html upon the closing of the popup? or is there an even better solution that I havent yet considered? ---
**Author:** ![david](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/aeb1de/32.png) [@david](https://www.ruby-forum.com/u/david)\ **Post date:** [January 26, 2009, 4:07am UTC](https://www.ruby-forum.com/t/ajax-partial-need-unique-ids/158628/2 "2009-01-26T04:07:45Z")
David wrote: > DOM with id “start\_time” and it doesnt work. My question is would it > be better to rename all the start\_time elements so that they are all > unique? or would it be better to somehow replace the html upon the > closing of the popup? or is there an even better solution that I > havent yet considered? You should generally get in the habit of uniquifying all HTML IDs. This is partly because it’s The Law (y’heah, right!), and partly so when you actually need them Your ID should be “start\_time\_\<%= @record.id %\>”, because your database IDs are generally unique to the system. Further, the View Tests on your partial, and on your ajax handler, should expect unique IDs. As a big digression, here’s how we do that at work. (If this code had used the @record.id trick, it would appear in the assertions!): ``` def test_render_skim_panel_cc site_list = sites(:doctors_site, :lawyers_site) render :partial => 'skim_panel', :locals => { :@sites => site_list, :@payment_method => 'cc' } assert_xpath :select, :cc_skim_selection do site.skims.visible('cc').each do |skim| option = assert_xpath(:option, :value => skim.id) assert{ option.text == skim.name } end site.skims.visible('ach').each do |skim| deny_xpath :"option[@value = '#{skim.id}']" end end end ``` (Parenthetically, can Merb’s fixtures return a list of records from one sites() call like that?) The test renders the partial that displays a panel containing a list of skims (aka “special offers”). The panel contains only Credit Card offers, no ACH (Checking) offers. The first assert\_xpath() call discovers the list with the correct name. The subsequent assertions must pass inside this list - another option in another panel cannot cause a false positive. The internal assert\_xpath() finds each CC skim in our model, and matches its name. I could have written assert\_xpath(“option[ @id = ‘#{skim.id}’ and @value = ‘#{skim.name}’ ]”), but running this XPath as a Ruby DSL saves a lot of ugly string-mashing code. Further, I can’t tell from the have\_xpath() documentation if you can nest the XPaths, or if you can use the returned node, like have\_xpath().text. I am aware of XPath functions such as contains(), but it seems that more complex sub-assertions, in the Ruby code, are impossible. The last assertion denies that the wrong skims appeared in the list. There are also lower-level tests on the model things that the partial calls, and there are higher level tests on the entire page containing this partial. Any port in a storm! This test covers one of the Ajax handlers. It returns JavaScript that pushes the ‘skim\_panel’ partial into the correct container: ``` def test_populate_empty_skim_list site_list = sites(:doctors_site, :lawyers_site) site_list.map(&:skims).map(&:destroy_all) xhr :post, :xhr_populate_skims, :sites => site_list assert_js_replace_html :skim_panel_cc do assert_xpath :select, :cc_skim_selection do deny_xpath '*' end end end ``` assert\_js\_replace\_html() lexes the returned JavaScript, and finds the Replace.element(‘skim\_panel\_cc’) call. Then it finds the string payload inside that, evaluates this as XHTML, and preps that to work with assert\_xpath(). The assert\_xpath() call detects the , and the nested deny\_xpath() simply determines that it is empty. The point of all this lexing and nesting is to pinpoint the regions that need test, and exclude the ones that don’t. If that deny\_xpath failed, its diagnostic would not report the entire page. It would only report the contents of the tag around the assertion. assert\_js\_replace\_html() works a lot like the ARTS assert\_rjs() call, but that only uses regular expressions. I told my colleague to use the latter this week, and he immediately discovered that a call like assert\_rjs :replace\_html, ‘skim\_panel\_cc’, /\