title: verify, if the string starts with given substring
body: <p>I have a string in <code>$str</code> variable.</p>
  <p>How can I verify if it starts with some word?</p>
  <hr />
  <p>Example:</p>
  <pre><code>$str = &quot;http://somesite.com/somefolder/somefile.php&quot;;
  </code></pre>
  <p>When I wrote the following script returns yes</p>
  <pre><code>if(strpos($str, &quot;http://&quot;) == '0') echo &quot;yes&quot;;
  </code></pre>
  <p>BUT it returns <strong>yes</strong> even when I wrote</p>
  <pre><code>if(strpos($str, &quot;other word here&quot;) == '0') echo &quot;yes&quot;;
  </code></pre>
  <p>I think <code>strpos</code> returns zero if it can't find substring too (or a value that evaluates to zero).</p>
  <p>So, what can I do if I want to verify if word is in the start of string? Maybe I must use <code>===</code> in this case?</p>