How to load dialog before php file.

How to load dialog before php file.

Hi everybody,
I need to know how can I load a dialog before  this:
$("<form method='post' action='registroQuadri1.php' target='_new'><input type=hidden name=a value='"+arg1+"'/><input name=b value='"+arg2+"'/></form>").appendTo("body").submit()

I've tried this:
$("#esegui").dialog({
            "title": "RegistroOnWeb - Attesa programma -",
            height: 150,
            width: 430,   
          })
$("<form method='post' action='registroQuadri1.php' target='_new'><input type=hidden name=a value='"+arg1+"'/><input name=b value='"+arg2+"'/></form>").appendTo("body").submit()

but dialog loads not on the _NEW page.

Please, can someone helps me?

Thans in advance

Tegatti