Simple task list frontend rewrite
Consider 

&lt;?php
    foreach ($taskData as $key =&gt; $value) {
        $class = ($value['status']) ? 'check-' : '';
        $trClass = ($value['status'] == 1) ? ' class="checkedTR"' : '';
        echo &lt;&lt;&lt;EOHTML
&lt;tr$trClass&gt;
  &lt;td onclick="toggleCheck($key, {$tasks['uid']}, 'task')" valign="middle" class="clickable"&gt;
    &lt;center&gt;
      &lt;i data-status="{$value['status']}" id="$key-task" class="fa fa-lg fa-{$class}circle-o" aria-hidden="true"&gt;&lt;/i&gt;
    &lt;/center&gt;
  &lt;/td&gt;
  &lt;td class="unselectable"&gt;{$value['task']}&lt;/td&gt;
&lt;/tr&gt;
EOHTML;
    }
?&gt;


I prefer the long versions of tags.  So no &lt;? or &lt;=.  It may not matter as much now, but it used to be that some sites would turn off the short versions.  So software could suddenly stop working for no apparent reason.  

I prefer to use single quotes in PHP unless I have to use double quotes, e.g. for variable interpolation.  This way I can see at a glance that a string is not using variable interpolation.  

If I'm working with a block of lines in PHP, I prefer to use Heredocs and Nowdocs.  I prefer Nowdoc, but it won't work here.  We need the variable interpolation.  The original code will put the entire thing on one line.  This version will display it more like it looks here.  

I prefer to use double quotes in HTML.  No particular reason except that it looks better to me.  

I prefer to avoid the $tasks[uid] syntax.  Outside of a string, it's wrong and unreliable.  Inside of a string it's reliable, but it can be misleading.  People see it working inside of a string and don't know why the behavior is special.  Also, if people copy something like $tasks[FIELD] into a string, it may not be obvious why it doesn't work the same way inside a string as outside.  Always using the curly braces is clearer in my opinion.  

In this case, I would pick the Javascript quoting to avoid escaping, i.e. single quotes.  

Your HTML indentation is inconsistent.  Sometimes two spaces and sometimes four.  

You lost a closing &lt;/td&gt; in the refactor.