方式一:
在事件中传入 window.event或者event或者arguments[0]

<button οnclick="rightClick1(window.event)" id="btn">右键</button>

function rightClick1(e){
        console.log(e);
      }

方式二:

<button οnclick="rightClick1()" id="btn">右键</button>

直接打印window.event或event

function rightClick1(){
        console.log(event);
        console.log(window.event);
      }

方式三

<button id="btn">右键</button>

为元素添加监听

document.getElementById("btn").addEventListener('click',function(e){
        console.log(e);
      })

获取的事件对象