st parameter will
contain the original string, the second will contain the phrase you wish
to highlight. The third and fourth parameters will contain the
opening/closing HTML tags you would like the phrase wrapped in.</p>
<p>Example:</p>
<div class="highlight-ci"><div class="highlight"><pre><span class="nv">$string</span> <span class="o">=</span> <span class="s2">&quot;Here is a nice text string about nothing in particular.&quot;</span><span class="p">;</span>
<span class="k">echo</span> <span class="nx">hi