JS响应事件 

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>JS响应事件练习</title>
    <meta charset="utf-8" />

</head>
<body>
    用户名： <input type="text" />
    <br />
    <br />
    <input type="button" value="确定" id="click" />
    <script>
        document.write("<br/>");
        btn = document.getElementById("click");
        btn.onclick = function () {
            alert("HelloWorld!")
        }
    </script>
    <img src="a.jpg" id="a" />

    <script>
        document.getElementById("a").onmouseover = function () {
            this.src = "b.jpg";
        }
        document.getElementById("a").onmouseout = function () {
            this.src = "a.jpg";
        }
    </script>


    <form id="form1" action="http://www.baidu.com">

        用户名：<input type="text" id="name" />
        <br />
        <br />
       <input type="submit" />

        <script>
            document.getElementById("form1").onsubmit = function () {
                name = document.getElementById("name").value;
                if (name =="") {
                    alert("请输入用户名");
                    return false;
                }
                return name;
            }
        </script>       
    </form>
</body>
</html>

 

posted @ 2018-01-05 10:50  你的斗志并没有失去  阅读(240)  评论(0)    收藏  举报