How to get html within the '<' and the '>' using Javascript?

Suppose I have the following code:
<h1>Header</h1>
<div id="identifier" class="classic" src="source" title="caption">
<p>Paragraph</p>
</div>
getElementById("identifier").innerHTML returns the string "<p>Paragraph</p>" and outerHTML returns all the html I wrote above as string too of course.

But what about the html within the '<' and '>'? This suppose to be "div id="identifier" class="classic" src="source" title="caption""

I want to get this string, but I don't find out how. I have already tried tagName, but it returns only the string "DIV". Please help!