为什么我的PHP / HTML标题颜色/边框没有显示在OLD IE浏览器中/而且它不是CSS

The below is my header: the following is my cookie in php

<header>

  <div id="first">
  <?php
    if ($visits > 1)
    {
      echo "Thanks for coming back for more laughs!!!";
    }
    else
    {
      // First visit
      echo 'Welcome to my website!';
    }
  ?>
  </div>

This is my h1, h2, images, a link, and another image

    <h1>The Good Clean Jokes And Riddles Website!</h1>
    <h2>Add & Search Jokes or Riddles</h2>
    <div>
       <img id ="funny" img src="images/funny.jpg" alt="funny"/>
       <img id ="dog" img src="images/pet.jpg" alt="dog"/>
    </div>
    <div id="a">
       <a href="?add" >Add New Joke or Riddle</a>
       <img id="bell" img src="images/bell1-c.gif" alt="bell">
    </div>
  </header>

Older versions of IE do not apply CSS rules to elements they don't recognize.
This includes newer HTML5 elements like <header>.

You can use HTML5Shim or Modernizr to fix that.