javascript doesnt run
im completly new to js , i made this form for a project we got @ university but js doesnt seem to work at all. I dont get any errors, it is just doesnt work ! I got my Javascript enabled , and i full disabled No script. 

    <!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">
    <head>
      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
      <link rel="stylesheet" type="text/css" href="<?php echo $_SESSION['css'];?>"/>
    
      
     <script type="text/javascript">
    
    
      function validate_f() {
    	var result=true;
    	var username=document.getElemenetById('username').value;
    	var illegalChars = /\W/;
    	var x=document.getElemenetById('email').value;
         	var pwd=document.getElemenetById('password').value;
    
    
      if (illegalChars.test(username) || username.length>25) {
    		result=false;
    
    		alert("Username must be latin chars and not more than 25 characters");
      }
    
    if (x==null || x=="" || username == null || username=="" || pwd == null || pwd == "" || afm == null || afm == "" ) {
    result=false;
    alert("you have to fill up all the Boxes dude");
    }
    	return result;  
    	
    } 
    <div id="main">
    <div id="formcontainer">
    <form id="data" name="data" action="connection.php" method="POST" on submit="return validate_f()">
    <table width="100%" cellpadding="3" cellspacing="2">
    <tr>
    	<td width="25%"> </td>
    </tr>
    <tr>
    	<td class="right" width="20%"> <strong> Username </strong> </td>
    	<td>
    	<input type="text" name="username" id="username" size="25" maxlength="25"/>
    </td>
    </tr>
    <tr>
    	<td class="right"> <strong> Password</strong> </td>
    	<td>
    	<input type="password" name="password" id="password" size="25" maxlength="25"/>
    </td>
    </tr>
    <tr>
    	<td class="right"> <strong> Email</strong> </td>
    	<td>
    	<input type="text" name="email" id="email"/>
    	</td>
    </tr>
    <?php
    /*
    <tr>
    <td class="right"> <strong> Security Code: </strong> </td>
    <td>
    <img src="CaptchaSecurityImages.php" alt="" />
    <input id="security_code" name="security_code" type="text" />
    </td>
    </tr>
    */
    ?>
    <tr>   
     <td>
              <input name="reset" type="reset" id="reset" value="Reset" />
              <input name="submit" type="submit" id="submit" value="Submit"/>
    
            </td>
    </tr>
    </table>
    </form>
    </div>
    
    </div>


javascript doesnt run
===

im completly new to js , i made this form for a project we got @ university but js doesnt seem to work at all. I dont get any errors, it is just doesnt work ! I got my Javascript enabled , and i full disabled No script. 

    <!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">
    <head>
      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
      <link rel="stylesheet" type="text/css" href="<?php echo $_SESSION['css'];?>"/>
    
      
     <script type="text/javascript">
    
    
      function validate_f() {
    	var result=true;
    	var username=document.getElemenetById('username').value;
    	var illegalChars = /\W/;
    	var x=document.getElemenetById('email').value;
         	var pwd=document.getElemenetById('password').value;
    
    
      if (illegalChars.test(username) || username.length>25) {
    		result=false;
    
    		alert("Username must be latin chars and not more than 25 characters");
      }
    
    if (x==null || x=="" || username == null || username=="" || pwd == null || pwd == "" || afm == null || afm == "" ) {
    result=false;
    alert("you have to fill up all the Boxes dude");
    }
    	return result;  
    	
    } 
    <div id="main">
    <div id="formcontainer">
    <form id="data" name="data" action="connection.php" method="POST" on submit="return validate_f()">
    <table width="100%" cellpadding="3" cellspacing="2">
    <tr>
    	<td width="25%"> </td>
    </tr>
    <tr>
    	<td class="right" width="20%"> <strong> Username </strong> </td>
    	<td>
    	<input type="text" name="username" id="username" size="25" maxlength="25"/>
    </td>
    </tr>
    <tr>
    	<td class="right"> <strong> Password</strong> </td>
    	<td>
    	<input type="password" name="password" id="password" size="25" maxlength="25"/>
    </td>
    </tr>
    <tr>
    	<td class="right"> <strong> Email</strong> </td>
    	<td>
    	<input type="text" name="email" id="email"/>
    	</td>
    </tr>
    <?php
    /*
    <tr>
    <td class="right"> <strong> Security Code: </strong> </td>
    <td>
    <img src="CaptchaSecurityImages.php" alt="" />
    <input id="security_code" name="security_code" type="text" />
    </td>
    </tr>
    */
    ?>
    <tr>   
     <td>
              <input name="reset" type="reset" id="reset" value="Reset" />
              <input name="submit" type="submit" id="submit" value="Submit"/>
    
            </td>
    </tr>
    </table>
    </form>
    </div>
    
    </div>

