console 命令行工具 X clear

console

function alertSecond(){
    alert("第2次");
}

function changeColor() {
    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 () 
    {
        //事件处理器和事件监听器
        var oBtn = document.getElementById("btn");
        oBtn.onclick = function () {
            alert("第1次");
        };
        oBtn.onclick = function () {
            alert("第2次");
        };
        /*oBtn.onclick = function () {
            alert("第1次");
            alert("第2次");
            alert("第3次");
        };*/

        var oBtn = document.getElementById("listenbtn");
        
        oBtn.addEventListener("click",function(){
            alert("第1次");
        },false);
        oBtn.addEventListener("click",alertSecond,false);
        oBtn.removeEventListener("click",alertSecond,false);

        var oPContent = document.getElementById("content");
        oPContent.addEventListener("click",changeColor,false);
        oPContent.addEventListener("click",changeBackgroundColor,false);

        var oBtn = document.getElementById("removeBtn");
        
        oBtn.addEventListener("click",function(){
            oPContent.removeEventListener("click",changeColor,false);
        },false);

        var oPContent1 = document.getElementById("content1");
        oPContent1.onclick=changeColorAndBackgroundColor;

        var oBtn1 = document.getElementById("removeBtn1");
        
        oBtn1.addEventListener("click",function(event){
            console.log(event.type);
            oPContent1.onclick=changeBackgroundColor;
        },false);

        document.addEventListener("keydown",function(event){
            console.log(event.type);
            if(event.shiftKey||event.altKey||event.ctrlKey){
                console.log("你按下了 shift,alt或者ctrl");
            }
            console.log("你按下了"+event.keyCode);
        })
        document.addEventListener("keyup",function(event){
            console.log(event.type);
            console.log("你松开了"+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>

        <button id="removeBtn">解除</button>
    </div>

    <div>
        <p id="content1">信息科学学院</p>

        <button id="removeBtn1">解除</button>
    </div>
</body>
</html>