After several days, finally I found how to make ajax call from my wordpress site, I hope that it will help those who have had this problem:
first, I was created a post inside a wordpress whit this html code:
<section id="main"> <table id="tng" class="datagrid"> <thead><tr><th colspan="3"> Sample ping App </th> </thead> <tbody> </tr><tr> <td width="50%" align="right"><b>Host or IP:</b></td> <td><input id="ip" size="20" value="" ></td> <td><button type="button" onclick="PING()">Ping</button></td> </tr> </tbody> </table> <img id="image" src="spinner.gif" alt="wait..." style="display: none;"> <br> </section> <section id=food> <h3 id="notification"></h3> </section>
As you can see the only important thing is the onclick event for the button that calls de functionPING()