How to output variables such as the current page's entry_id in the script tag

Question

One one of our sites, we have ChannelFiles add-on installed and in the control panel (when editing an entry) it outputs a useful set of variables (see attached). But this is only part of add-on and if it's not installed, those variables aren't outputted. Is there anyway I can output these variables without ChannelFiles?

Background: There are certain fields that I only want to ever appear when editing a specific entry so I include a bit of jquery in the field instruction to hide/show field by checking against the variables outputted by ChannelFiles add-on in the script tag.

http://imagebin.org/258416

Thanks

UPDATE (to clarify): I need this when editing the entry in the control panel of EE (see Background section on why) and not in the front end. As far as I know, I don't have access to the templates for the control panel (or do I?).

Answer 1

You can output entry ids from within the channel:entries tag pair like this:

{exp:channel:entries channel="my_channel"}
  entry_id: {entry_id}<br>
{/exp:channel:entries

The Channel Entries documenation at EllisLab provide all the variable options available to you.

Update

You can add this script to any of the field's Field Instructions section.

<script>
  $(document).ready(function() {
    entryId = (document.URL).split('entry_id=')[1].replace(/\D/g,'');
    $('.heading h2').append(' #' + entryId); // adds to heading at top of form
    alert("entry id = " + entryId);
  });
</script>

Second Update

The previous script wasn't removing numerical characters from the url that occurred after the entry_id. The problem is that EE encodes the & as &. So here's this:

<script>
  $(document).ready(function() {
    firstPart = (document.URL).split('entry_id=')[0];
    entryId = (document.URL).split('entry_id=')[1].split(firstPart[firstPart.length -1])[0];
    $('.heading h2').append(' #' + entryId);
  });
</script>

Answer 2

I'd output the entry_id to the page as a hidden value, much as Stephen suggested, and then look to grab that with JavaScript. If you're viewing a specific entry_id for the page you're viewing then you made need to pass that in as a parameter:

{exp:channel:entries channel="my_channel" entry_id="{entry_id}"}
    <p class="hidden">entry_id: {entry_id}</p>
{/exp:channel:entries}

If you're just looking to use JS to show and hide specific fields depending on an entry ID however then you could do that purely on the server-side:

{if entry_id="10"} ... {/if}

This would have the benefit of being usable by those without JS enabled too.