下面介绍几种javascript中常用的表单事件:

        <form name="testform" action="#" id="form">
            What is your name?<br />
            <input type="text" name="fname" />
            <input type="submit" value="Submit" />
        </form>
        <script type="text/javascript">
            var form = document.getElementById('form');
            form.onsubmit = function(){
                alert('Hello ' + testform.fname.value +'!');
            }
        </script>

        <p>请输入你的英文名字: <input type="text" id="fname"></p>
        <p>请输入你的年龄: <input type="text" id="age"></p>
        <script type="text/javascript">
            function upperCase(){
                var x=document.getElementById("fname").value;
                document.getElementById("fname").value=x.toUpperCase();
            }
            
            var fname = document.getElementById('fname');
            var age = document.getElementById('age');
            fname.onblur = function (){
                upperCase();
            }
            age.onblur = function (){
                alert('age is ' + this.value);
            }
        </script>

        <!--onfoucs事件-->
        <p>第一个：<input type="text" onfocus="setStyle(this.id)" id="fname-foucs"></p>
        <p>第二个：<input type="text" onfocus="setStyle(this.id)" id="lname-foucs"></p>
        <script type="text/javascript">
            function setStyle(x) {
                document.getElementById(x).style.background = "yellow";
            }
        </script>

        <!--onchange事件-->
        <p>输入您的姓名：<input type="text" id="fname-change" onchange="upperCase(this.id)" /></p>
        <script type="text/javascript">
            function upperCase(x) {
                var y = document.getElementById(x).value;
                document.getElementById(x).value = y.toUpperCase();
            }
        </script>

        <script type="text/javascript">
            window.onload = function(){
                alert('页面加载已完成，会执行之后的代码');
            }
        </script>