how to use beforeSend option in $.post()
<p>I'm using ajax and I use beforeSend option in It .. But I want to know how to use 
beforeSend option  in $.post() ...</p>

<p>my ajax code : </p>

<pre><code>$.ajax({
    type: 'POST',
    url: url,
    data: data,
    beforeSend: function () {
        //some condition 
    },
    success: function (){},
    error: function () {}
});
</code></pre>

<p>In $.post() :</p>

<pre><code>$.post(url, data, function())
</code></pre>

<p>But when to add beforeSend option</p>