How to login in same or other window with controlled size

<?xml version="1.0" encoding="[CONTENT_ENCODING/]"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="[LANG_CODE/]" lang="[LANG_CODE/]" dir="[BASE_DIRECTION/]">

<head>
	<meta http-equiv="Content-Type" content="[CONTENT_TYPE/]" />
	<title>Micro Customer Care</title>
	<style type="text/css">
		body {
			padding:0;
			margin:0;
		}
	</style>
	[STYLE_SHEETS/]
	<!--[if lt IE 7]>
		<link rel="stylesheet" type="text/css" href="css/ie5-6.css"/>
	<![endif]-->
	<script src="js/chat.js" type="text/javascript" charset="UTF-8"></script>
	<script src="js/lang/[LANG_CODE/].js" type="text/javascript" charset="UTF-8"></script>
	<script src="js/config.js" type="text/javascript" charset="UTF-8"></script>
	<script type="text/javascript">
		// <![CDATA[
		
		function OnSubmit()
{	//alert("Ankit");
    var x=document.forms["myForm"]["userName"].value;
   if (x==null || x=="")
  {
  alert("User name must be filled out");
  return false;
  }
  var x=document.forms["myForm"]["email"].value;
   if (x==null || x=="")
  {
  alert("E-mail must be filled out");
  return false;
  }
	var x=document.forms["myForm"]["email"].value;
var atpos=x.indexOf("@");
var dotpos=x.lastIndexOf(".");
if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length)
  {
  alert("Not a valid e-mail address");
  return false;
  }
    
    document.getElementById('loginForm').action = "formData.php",// Second target
	document.getElementById('loginForm').target = "_self";	 // Open in a iframe
	document.getElementById('loginForm').submit();
	document.getElementById('loginForm').action = "[LOGIN_URL/]"// Second target
	document.getElementById('loginForm').target = "_self";	 // Open in a iframe
	document.getElementById('loginForm').submit();
	window.open("[LOGIN_URL/]","_blank","width=400, height=400");
	
	
	return true;
}
			function initializeLoginPage() {
				document.getElementById('userNameField').focus();
				if(!ajaxChat.isCookieEnabled()) {
					var node = document.createElement('div');
					var text = document.createTextNode(ajaxChatLang['errorCookiesRequired']);
					node.appendChild(text);
					document.getElementById('errorContainer').appendChild(node);
				}
			}
			
			ajaxChatConfig.sessionName = '[SESSION_NAME/]';
			ajaxChatConfig.cookieExpiration = parseInt('[COOKIE_EXPIRATION/]');
			ajaxChatConfig.cookiePath = '[COOKIE_PATH/]';
			ajaxChatConfig.cookieDomain = '[COOKIE_DOMAIN/]';
			ajaxChatConfig.cookieSecure = '[COOKIE_SECURE/]';

			ajaxChat.init(ajaxChatConfig, ajaxChatLang, true, true, false);
		// ]]>
	</script>
</head>

<body onload="initializeLoginPage();">
	<div id="loginContent">
		<div id="loginHeadlineContainer">
			<h1>Micro Customer Care</h1>
		</div>
			<form id="loginForm" name="myForm" action="[LOGIN_URL/]" method="post" enctype="application/x-www-form-urlencoded" >
				<div id="loginFormContainer">
					<!--<input type="hidden" name="login" id="loginField" value="login"/>
					<input type="hidden" name="redirect" id="redirectField" value="[REDIRECT_URL/]"/>-->
					<div><label for="userNameField">[LANG]userName[/LANG]:</label><br />
					<input type="text" name="userName" id="userNameField" maxlength="[USER_NAME_MAX_LENGTH/]"/></div>
					<div><label for="passwordField">Email:</label><br />
					<input type="text" name="email" id="passwordField"/></div>
					<!--<div><label for="channelField">[LANG]channel[/LANG]:</label><br />
					<select name="channelName" id="channelField">[CHANNEL_OPTIONS/]</select></div>
					<div><label for="languageSelection">[LANG]language[/LANG]:</label><br />
					<select id="languageSelection" name="lang" onchange="ajaxChat.switchLanguage(this.value);">[LANGUAGE_OPTIONS/]</select></div>-->
					<div><input type="submit" value="[LANG]login[/LANG]" name="button1" id="loginButton"  onclick="return OnSubmit();"/></div>
					<!--<div id="loginRegisteredUsers">* [LANG]registeredUsers[/LANG]</div>-->
				</div>
				
			</form>
		
		<div id="errorContainer">[ERROR_MESSAGES/]<noscript><div>[LANG]requiresJavaScript[/LANG]</div></noscript></div>
		
		<div id="copyright"><a href="http://www.microtechnologies.net/">Micro</a> &copy; <a href="http://www.microtechnologies.net/">Microtechnologies.net</a></div>
	</div>
	<div style="visibility:hidden">
     <iframe NAME="iframe2" WIDTH="40" HEIGHT="40" ></iframe>
	</div>
</body>

</html>

HI friends…
I have a login page. I want when user click on Login button it redirects to same or another window but with controlled size i.e. it should be pop up of user home page after login.
I used

window.open("[LOGIN_URL/]","_blank","width=400, height=400");

for creating pop-up but problem is that pop-up not displays user’s home page instead it displays login page again(which is not required).
Can I any one tell me how to create a pop-up which displays user’s home page???
Please help me…
Thanks in advance…

window.open("[LOGIN_URL/]","_blank","width=400, height=400");

shouldn’t it be:

window.open("[HOMEPAGE_URL/]","_blank","width=400, height=400");

new window must display the homepage and not the login page

specify the url of the new window to be the url of the homepage