Unrecognised expression with error for ids starting with an integer

Question

I'm trying to grab an element from a page which has an id starting with an integer.

$('#3|assets_main|ast_module|start-iso-date')

I get the following error

Uncaught Error: Syntax error, unrecognized expression: |assets_main|ast_module|start-iso-date

I am using jQuery 1.7.1, I understand that the id in general is poorly named but is there any reason why jQuery will has issues with ids that start with integers?

IDs are supposed to start with a letter. What you have is basically invalid. The error is to be expected. — VLAZ, Oct 14 '16 at 15:52
Also, yeah, I just realised - are the `|` also part of the ID? Because those would also be invalid. — VLAZ, Oct 14 '16 at 15:53
@vlaz not true in HTML5. Ids can contain any character at any position except spaces. — Rory McCrossan, Oct 14 '16 at 15:53
@vlaz yes I understand that it is poorly named, but I do not have the luxury of refactoring the code. — mk_89, Oct 14 '16 at 15:57
@vlaz HTML5 allows anything but spaces https://www.w3.org/TR/html5/dom.html#the-id-attribute and HTML4 only disallowed special characters not digits — Matthew M. Osborn, Oct 14 '16 at 16:00
Possible duplicate of [jquery selector doesnt accept pipe character |?](http://stackoverflow.com/questions/12306252/jquery-selector-doesnt-accept-pipe-character) — Jordan Gray, Oct 14 '16 at 16:09

Rory McCrossan · Accepted Answer · 2016-10-14T15:54:42.793

4

In HTML5 the id can start with a numerical value, so your id is valid.

The issue is the pipe (|) characters in the selector; you need to escape them using \\:

$('#3\\|assets_main\\|ast_module\\|start-iso-date')

Working example

edited Oct 14 '16 at 15:54

answered Oct 14 '16 at 15:53

Rory McCrossan

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I thought, this may have been the case, so I tried the same but it did not fix my problem. – mk_89 Oct 14 '16 at 15:54
Are you sure? Because it works fine here: https://jsfiddle.net/rbqaLd72/ – Rory McCrossan Oct 14 '16 at 15:54
It does not throw an error but it also can't find the element on the page – mk_89 Oct 14 '16 at 15:57
1

Have you ensured the element exists when you call this line of code? As you can see from the example, there's no reason this wouldn't work if the id values match – Rory McCrossan Oct 14 '16 at 15:59

Unrecognised expression with error for ids starting with an integer

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