getelementbyid and tagname and classname
<p>I want to know how you can get element using pure javascript.</p>

<p>I have my code below:</p>

<pre><code>        &lt;html&gt;
             &lt;body&gt;
                 &lt;div id="abc" class="xy"&gt; 123 &lt;/div&gt;
                &lt;p id="abc" class="xyz"&gt; 123 &lt;/p&gt;
              &lt;span id="foo" class="foo2"&gt; foo3 &lt;/span&gt;
             &lt;/body&gt;
           &lt;/html&gt;
</code></pre>

<p>Here i want to find element with combination:</p>

<ol>
<li>find element has id abc and tagname p</li>
<li>find element has id abc and classname xy</li>
<li>find element has classname foo2 and tagname span</li>
<li>find element has id abc and classname xy and tagname div</li>
</ol>

<p>I know we can't use more than one id per page. But in worse situation is it ok to have same ID to different tags? in html?</p>
