jquery equivalent to javascript piece of the code
<p>I have this part of the code which works very well on javascript:</p>

<pre><code>document.getElementById("firma").onkeypress = function(e) {
return restrictCharacters(this,e,alphaOnly); 
};
</code></pre>

<p>i'ts part of some script and this part joins it on id="firma"</p>

<p>I'm courious to know what is equivalent if this code in jquery?</p>

<p>it's something like $( "#firma" ).....</p>
