console 命令行工具 X clear

console

function alertSecond(){
    alert("第二次");
}

function changeColor(){
    if(this.style.color=="red"){
        this.style.color="black";
    }
    else{
        this.style.color="red";
    }
}
function changeBack(){
    if(this.style.color=="red"){
        this.style.color="black";
    }
    else{
        this.style.color="red";
    }
}
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1次");
            alert("第2次");
            alert("第3次");
        };
        

        var oBtn=document.getElementById("listenBen");

        oBtn.addEventListener("click",function(){
            alert("第1次");
        },false);
        oBtn.addEventListener("click",alertSecond,false);
        oBtn.removeEventListener("click",alertSecond,false);

        var oPContent=document.getElementById("removeBtn");
        oPContent.addEventListener("click",changeColor,falese);
        oPContent.addEventListener("click",change,falese);
        

        oBtn.addEventListener("click",function(){
            oPContent.removeEventListener("click",changeColor,false);
        },false);



}

<!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>
        <p id="content">信息科学学院</p>

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

    </div> 
</body>
</html>