.ajax and append

.ajax and append

Hello guys, I'm new with jQuery and I'm having some trouble on the following function:

$("#fmphotos").click(function(){            
   $.ajax({
           type: "GET",
           url: "index.php",
           data: "p=311&g=311",
      success: function(msg){
         $("#cgallery").append(msg);
         alert("Ready!");
      },
      error: function(){
         $("#cgallery").append("Error.");
      }
   });

       $("#cgaleria").stop();
        $("#cgaleria").slideDown(1500);
});


When I click on the div #fmgallery, the animation works fine and I get the "Ready!" alert by JavaScript, but the content of my index.php?p=311&g=311 is not loaded inside the #cgallery...

The content of my index.php?p=311&g=311 is:

<br><br>
      <div id='myImageFlow' class='imageflow'>
         <img src="transformers2_set_9-150x155.jpg" longdesc="transformers2_set_9.jpg" width="150" height="155"  alt="" />
         
         <img src="transformers2_set_8-150x201.jpg" longdesc="transformers2_set_8.jpg" width="150" height="201"  alt="" />
         
         <img src="transformers2_set_10-150x206.jpg" longdesc="transformers2_set_10.jpg" width="150" height="206"  alt="" />
         
         <img src="transformers2_set_7-150x189.jpg" longdesc="transformers2_set_7.jpg" width="150" height="189"  alt="" />
         
         <img src="transformers2_set_11-150x175.jpg" longdesc="transformers2_set_11.jpg" width="150" height="175"  alt="" />
         
         <img src="transformers2_set_14-150x100.jpg" longdesc="transformers2_set_14.jpg" width="150" height="100"  alt="" />
         
         <img src="transformers2_set_12-150x225.jpg" longdesc="transformers2_set_12.jpg" width="150" height="225"  alt="" />

         
         <img src="transformers2_set_15-150x225.jpg" longdesc="transformers2_set_15.jpg" width="150" height="225"  alt="" />
         
         <img src="transformers2_set_13-150x161.jpg" longdesc="transformers2_set_13.jpg" width="150" height="161"  alt="" />
         
         <img src="transformers2_set_6-150x56.jpg" longdesc="transformers2_set_6.jpg" width="150" height="56"  alt="" />
         
         <img src="transformers2_set_5-150x70.jpg" longdesc="transformers2_set_5.jpg" width="150" height="70"  alt="" />
         
         <img src="transformers2_set_4-150x62.jpg" longdesc="transformers2_set_4.jpg" width="150" height="62"  alt="" />
         
         <img src="transformers2_set_3-150x78.jpg" longdesc="transformers2_set_3.jpg" width="150" height="78"  alt="" />
         
         <img src="transformers2_set_2-150x112.jpg" longdesc="transformers2_set_2.jpg" width="150" height="112"  alt="" />
         
         <img src="transformers2_set_1-150x74.jpg" longdesc="transformers2_set_1.jpg" width="150" height="74"  alt="" />
         </div>


Any ideas about this?

And, another thing, is there a way to check if the content has already been uploaded so this function won't play again if the user press it twice?