issues with using form in php

["Sudhakar" <finals27@xxxxxxxxx>]

i have 3 pages page1.php page2.php and page3.php 

in page1.php user fills a registration form in page2.php the user 
can review what they have entered and make any changes and 

page3.php displays a message that the registration has been 
completed.

i am having issues with javascript validation in page2.php 

in page1.php the javascript validation file is file1.js and in 
page2.php it is file2.js in page1.php the javascript code i 

have written works fine and does all the validation as the form 
elements in page1.php are written as 
<input type="text" name=""> <input type="radio" name=""> ...

in page2.php i am displaying these form elements using php so that 
user can preview what they have entered and make changes 

instead of going back to page1.php the code to display the form 
elements in page2.php is 

<?php 
echo "<input type ='hidden' name='username' value='".stripslashes
($username)."'>"; 
echo "<input type =\"text\" name=\"username\" value=\"$username\">";
?>

in page2.php for checkboxes the code is <input type="checkbox" 
name="" value=""> which is normal html unlike the textfields 

above using php

what i have noticed in page2.php is the checkboxes are being 
validated however the text fields in page2.php do not validate 

properly and does not work as it works in page1.php

what i am thinking is because the textfields are being generated 
using the above php code the javascript is not reading and 

validating however i am not sure what the exact reason is.

sample code of javascript for file1.js is 

var username = document.registrationform.username
if ((username.value==null) || (username.value=="") || 
(username.length=="") )
{
		alert("Please Enter a User Name")
		username.value=""
		username.focus()
		return false
}

sample code of javascript for file2.js is 

var fname=document.registrationform.fname
if ( (fname.value==null) || (fname.value=="") || (fname.length=="") )
{
		alert("First Name is required")
		return false
}
also sometime if i use fname.value in page2.php i get an error that 
value is not an object or is null so i have modified the 

code in file2.js to some extent


can some one tell me how to go about validating textfields and other 
form elements in page2.php using php code to be 

validated like the checkboxes in page2.php

any help will be greatly appreciated.


also in page2.php i have an insert statement which writes the 
information that a user has entered in the form into mysql 

database. i have read about database injection recently. so i have 
used $username  = addslashes($_POST["username"]);		
due to this the value in the database is recorded as example 
first\name if a user typed first'name in the form should i use 
mysql_real_escape_string() method to take extra precaution or is 
addslashes() method alright. if i adopt 

mysql_real_escape_string() do i just read the values simply as 
$username = mysql_real_escape_string($_POST["username"]);
or do i need to write extra code because of using 
mysql_real_escape_string() method 	

thanks.