Appears to be here:

"function registerValidator(e) {
e.targetElement = findFollowingTR(e, "validation-error-area").firstChild.nextSibling;
e.targetUrl = function()

;"

Where "this.getAttribute("checkUrl")" blows up because checkUrl contains something like: "'/checkDisplayName?displayName='encodeURIComponent(this.value)'&jobName='+encodeURIComponent('Job with single'quote')"

I have also experienced this issue in our Jenkins 1.478 on Windows Server 2003. I've confirmed the issue in IE, Firefox, Chrome, and Opera.

I do not reproduce the issue using Jenkins 1.534 and Firefox or Chrome.
Can we close this?

Cannot reproduce in 1.563. Browser console also shows numerous successful requests that seem related, e.g.

http://localhost:8080/job/This%20won%27t%20work/descriptorByName/hudson.model.FreeStyleProject/checkAssignedLabelString?value=

Env: Jenkins 1.589 on Centos 6.5
Browser: Chrome 38.0.2125.111 on Windows 8.1

Problem: Job with a Maven project name containing 'something' in between. For example, Job with a name: CI build and Test 'master' branch

When trying to re-configure the Job:

• stalls on Loading (which doesn't actually prevent trying to edit, since not spanning over the whole view)
• from the failing 404 GET requests one can identify that it appends / char before ' char on some requests. By executing these request directly without the appended / character before the ' char they do work.
• One can swap through the HTML elements with tab and press to Save (wanted to fix the Job by renaming the project) which produces an Error: JSONObject["scm"] is not a JSONObject

When trying to Delete Maven Project:

• Uncaught SyntaxError: Unexpected identifier

I can confirm much of what harmia describes on 1.586, except that it's backslashes instead of forward slashes. Most of the impact seems to stem from buggy escaping in the Javascript.

User error but this may help someone:

I encountered this issue with Jenkins 2.235.1. In addition to the above, my browser also reported a bad Content Security Policy for some of the resources. I resolved this by removing the Content-Security-Policy header in my reverse proxy config, instead letting Jenkins handle this header.