Hi there guys I wanted to know what is the "this" element in the following two codes and what it does?

Code:
<h1 onclick="this.innerHTML='Ooops!'">Click on this text!</h1>
Code:
<div onmouseover="mOver(this)" onmouseout="mOut(this)" style="background-color:#D94A38;width:120px;height:20px;padding:40px;">Mouse Over Me</div>
thanks.