What does this mean?

Do not link to an anchor on the page that does not exist. For example: linking to #content without a valid destination such as <body id="content"></body>.

A common web design pattern is to use a named anchor to show an element via JavaScript, e.g.

<a href="#foo" onclick="$('.bar').toggle();">Click me</a>
<div class="bar">
    This is some content.

In these cases, the anchor (#foo) should point to the id of the hidden element:

<a href="#foo" onclick="$('#foo').toggle();">Click me</a>
<div id="foo">
    This is some content.

This way the semantic intent of the link is preserved, even without JavaScript. Note that doing so may require modification to your script, to prevent automatic scrolling to the named anchor.

89.6% done

How close this website is to fixing this issue.

HTML Found on page Issues
<a href="#80" title="Give AMD patient day 4/5">Give AMD patient day 4/5</a> 1
<a href="#40" title="Give Meet the governors 2/5">Give Meet the governors 2/5</a> 1
<a href="#!/job_list/s7/Administrative_Services?_ts=1" class="sector7" title="Search for Administrative Services jobs">...</a> 1
<a href="#20" title="Give Know Your Drops - new dates announced 1/5">Give Know Your Drops - new dates announced 1/5</a> 1
<a href="#20" title="Give Eye to Eye 2017 1/5">Give Eye to Eye 2017 1/5</a> 1
<a href="#100" title="Give Our new website 5/5">Give Our new website 5/5</a> 1
<a href="#80" title="Give Top tips for managing hay fever symptoms 4/5">Give Top tips for managing hay fever symptoms 4/5</a> 1
<a href="#20" title="Give Meet the governors 1/5">Give Meet the governors 1/5</a> 1
<a href="#60" title="Give Eye to Eye 2017 3/5">Give Eye to Eye 2017 3/5</a> 1
<a href="#80" title="Give Glaucoma 4/5">Give Glaucoma 4/5</a> 1
65 distinct issues were found in the sample of 125 web pages. Only the first 10 issues are shown here.
More results from Moorfields Eye Hospital NHS Foundation Trust