JS事件
1.事件绑定 < button id = "btn" > 测试 < / button > < script > var btn = document . getElementById ( "btn" ) btn . addEventListener ( "click" , event => { alert ( event . target ) } ) < / script > ` 2.事件冒泡 < body > < div id = "div1" > < p > 这是p1 < / p > < p > 这是p2 < / p > < p > 这是p3 < / p > < p > 这是p4 < / p > < / div > < / body > < script > let body = document . body ; body . addEventListener ( "click" , event => { console . log ( "body click" ) ; console . log ( event . target ) ; } ) let div1 = document . getElementById ( "div1" ) ; div1 . addEventListener ( "click" , event => { event .