Site is reloading by itself
===

i have the following site, which makes a callback to a different domain.

    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    	<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    	<title> Example Entry Form </title>
    	
    	<script src="http://code.jquery.com/jquery-1.7.2.js" type="text/javascript"></script>
    	<script type="text/javascript">
    	function getParameters(){
    		// login
    		//window.showModalDialog('http://localhost:8080/test/login/check.mvc','','dialogWidth:500px; dialogHeight:350px; resizable:no; unandorned:yes; status:no; ');
    		//get data
    		$.getJSON('http://localhost:8080/test/secure/profile/services/export/getuser.mvc?callback=?',function(res){
    			alert('Your name is '+res.lname);
    			$('#lastname').val(res.lname);
    			$('#firstname').val(res.fname);
    			$('#club').val(res.club);
    			$('#phone').val(res.phone);
    			$('#mobile').val(res.mobile);
    			$('#mail').val(res.email);
    			$('#street_nr').val(res.streetNr);
    			$('#zip_city').val(res.zip + " " + res.city);
    			$('#birthday').val(res.birthday);
    		})
    		.error(function(){
    			alert("Error");
    		})
    		.complete(function(){
    			alert("Complete");
    		});
    		alert("Script End!");
    	}
    	</script>
    </head>
    
    <body >
    
    	<h1>Entry Form</h1>
    
    	<table>
    	 <tr>
    	  <td style="width:400px;">
    		<form action="save.php" id="FormName">
    			<table>
    				<tr>
    					<td>Lastname:</td>
    					<td><input type="text" id="lastname"/></td>
    				</tr><tr>
    					<td>Firstname:</td>
    					<td><input type="text" id="firstname"/></td>
    				</tr><tr>
    					<td>Club:</td>
    					<td><input type="text" id="club"/></td>
    				</tr><tr>
    					<td>Mobile:</td>
    					<td><input type="text" id="mobile"/></td>
    				</tr><tr>
    					<td>Telephone:</td>
    					<td><input type="text" id="phone"/></td>
    				</tr><tr>
    					<td>eMail:</td>
    					<td><input type="text" id="mail"/></td>
    				</tr><tr>
    					<td>Street+Nr:</td>
    					<td><input type="text" id="street_nr"/></td>
    				</tr><tr>
    					<td>ZIP+City:</td>
    					<td><input type="text" id="zip_city"/></td>
    				</tr><tr>
    					<td>Birthday:</td>
    					<td><input type="text" id="birthday"/></td>
    				</tr><tr>
    					<td>&nbsp;</td>
    					<td><button type="submit">Send Form</button>
    				</tr>
    			</table>
    		</form>
    	  </td>
    	  <td valign="top">
    		<a href="" onclick="getParameters();"><img src="script/pic.png" alt="Get Data"/></a>
    	  </td>
    	 </tr>
    	</table>
    </body>
    </html>

The stated script works fine, except for two major problems:

 1. it only works, when there is an alert(); in the script, which is not in the &.getJSON() function.
 2. after the last alert(); fires ("End of Script!") the site is reloading (the browser says: http://code.jquery.com/ -> the jquery script) and after being finished. All data are gone.

Why? And how can I fix this?