Jquery's first day of learning: Line-changing, text box focus clearing, and show shrinking Effect

Jquery is also frequently used. prototype And mootools are also widely used. I have never carefully read jquery selector, DOM, and animation effects. I have bought a book and want to finish it this month, it indicates that I have read the selector and occasionally record some common effects,

Jquery is also frequently used. prototype And mootools are also widely used. I have never carefully read jquery selector, DOM, and animation effects. I have bought a book and want to finish it this month, it indicates that I have read the selector, and occasionally record some common effects without details. I want to use it myself in the future:

1. jquery line-changing effects: