input.php

<h2>Test of _POST for LaTeX</h2>
<p>Post a LaTeX string here.</p>

<form action="pLaTeX.php" method="post">
<p>
    <label>Test string: </label>
    <input type="text" name="formula" value="11.$\sqrt{2}$"/><br/>
</p>
<p>
    <input type="submit" value="Submit"/>
</p>
</form>