Remember when you were a child and you'd goof off with a calculator and multiply two really big numbers together and get that display with an E in it?

Well that is what is known as scientific notation a subset of floating-point numbers (E for exponent) and the existence of these means that you may type a lowercase e or an uppercase E into an HTML element like this...

<input id="foo" type="number">

 
 

...and that kinda sucks.