My code on website is not validate on W3 Validator.

<?xml version="1.0" encoding="ISO-8859-1"?>
  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"


<title> Contact </title>

<meta name="description" content="Inzenjerski portal,baza znanja,vesti,seme,desavanja"/>
<meta name="keywords" content="Automatika,PLC,frekventni regulatori,arduino"/>
<meta name="author" content="Nikola Krga"/>
<meta name="robots" content="noindex, nofollow"/>
<link type="text/css" rel="stylesheet" href="about.css"/>

<table bgcolor="#b5a789" align="center" width="100%" border="1" cellpadding="10" cellspacing="6">

<td bgcolor="#675c47" align="center"><font size="5" color="blue" >Contact</font></td>
<td align="center" bgcolor="efe5d0" >

<div id="nav">
<a href="projekat1.php" >HOME</a>
<a href="about.php" >ABOUT</a>
<a href="contact.php" >CONTACT</a>


<tr class="main">

<ul type="circle">
<li><font color="blue" size="5">Arduino</font></li>
<li><font color="blue" size="5">tel:+38122656454</font></li>
<li><font color="blue" size="5">mob:+381642564829</font></li>
<li><font color="blue" size="5"></font></li>

<td align="center" bgcolor="#675c47" width="100%" colspan="3">
© 2014, ARDUINO
      All trademarks and registered trademarks appearing on 
      this site are the property of their respective owners.
 <br/><a href="http://validator.w3....">Validator</a>



And it tells you exactly why it failed.
Add the xlmns to the html element and adjust the DOCTYPE as it suggests.
You did read the output from the validator didn't you?

Member Avatar for diafol

Although it may not be totally relevant, why using XHTML? Reason why you're not using HTML5? The html you display is horribly out of date. <font> tags should never be used - use CSS. Same applies to some other tag attributes/properties. Hardcoding styling into HTML makes it very difficult to maintain and to apply "themes". The HTML looks like something from the early 90's. Is it?

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