https://codepen.io/anon/pen/P.

my code is like above, when you hold down the mouse and drag the red block, when you move quickly, it often won"t move.

but I took a look at what other people wrote will not be like this, ah, which is the key part of me that did not do it?

Please open it with the latest chrome, regardless of the new method of html5 for the time being

good example
http://v5cy.cn:8088/git/drag/
http://jerryc8080.github.io/d.