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() {
    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");

    var oBtn1 = document.getElementById("removeBtn1");

     oBtn1.addEventListener("click", function(event){
        alert(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>

        <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>