SOURCE

console 命令行工具 X clear

                    
>
console
 function alertSecond (){
     alert("2")
 }
 function changeco(){
   
         this.style.color="red"
 }
  function changecoback(){
     if(this.style.color=="red"){
         this.style.color="black"
     }else{
         this.style.color="red"
     }
 }

 function changeBackgroundColor() {
    console.log(this.textContent);
    if (this.style.backgroundColor == "lightskyblue") {
        this.style.backgroundColor = "white";
    }
    else {
         this.style.backgroundColor = "lightskyblue";
    }
   
}

function changeColorAndBackgroundColor() {
    
    if (this.style.color == "red") {
        this.style.color = "black";
    }
    else {
         this.style.color = "red";
    }
     if (this.style.backgroundColor == "lightskyblue") {
        this.style.backgroundColor = "white";
    }
    else {
         this.style.backgroundColor = "lightskyblue";
    }

}
  window.onload = function () 
        {
            var oBtn = document.getElementById("btn");
            oBtn.onclick = function () {
                alert("第1次");
            };
            oBtn.onclick = function () {
                alert("第2次");
            };
            oBtn.onclick = function () {
                alert("第3次");
            };

              var oBtn = document.getElementById("listenbtn");
              oBtn.addEventListener("click",function(){
                  alert("第一次");},false);
                oBtn.addEventListener("click",alertSecond,false);
            //  oBtn.removeEventListener("click",alertSecond,false);

       var ocontent =document.getElementById("content")
           ocontent .onclick=function(){
         ocontent.addEventListener("click",changeco,false)
          ocontent.addEventListener("click",changecoback,false)
       }
         var rebutton =document.getElementById("rebutton")
         
         rebutton.addEventListener("click",function(){
            ocontent.removeEventListener("click",changeco,false)
         },false)
         
           var ocontent1 =document.getElementById("content1")
           ocontent1 .onclick=changeco;

        var rebutton1 =document.getElementById("rebutton1")
         rebutton1.addEventListener("click",function(){ocontent1.onclick=null;
         },false)

       document.addEventListener("keydown", function(event) {
        console.log(event.type);
        if (event.shiftKey || event.altKey || event.ctrlKey){
            console.log("你按下啦 shift, alt 或者ctrl");
        }
        console.log("你按下啦 " + event.keyCode);
    }, false);

    document.addEventListener("keyup", function(event) {
        console.log(event.type);
        console.log("你松开啦 " + event.keyCode);
    })

       }

         

        
<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
      
    </script>
</head>
<body>
    <input id="btn" type="button" value="按钮"/>
    </br>
      </br>
    <input id="listenbtn" type="button" value="监听按钮"/>

    <div>
<p id="content">广州新华学院</p>
</br>
<button id="rebutton">解除</button>
    </div>

    <div>
<p id="content1">信息科学学院</p>
</br>
<button id="rebutton1">解除</button>
    </div>
</body>
</html>