To move elements around we should be familiar with coordinates. Most JavaScript methods deal with one of two coordinate systems: Relative to the window – similar to position:fixed, calculated from the window top/left edge. we’ll denote these coordinates as clientX/clientY, the reasoning for such name will become clear later, when we study event properties. Relative to the document – similar to pos
![Coordinates](https://cdn-ak-scissors.b.st-hatena.com/image/square/381cb4134c53c5788aa6b7a2cedf7f2fbc019b01/height=288;version=1;width=512/https%3A%2F%2Fjavascript.info%2Fimg%2Fsite_preview_en_1200x630.png)