js表单操作

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<script>
window.onload = function() {
    
    var oForm = document.getElementById('form1');
    //var oText = document.getElementById('text1');
    
    //获取表单中一个元素  表单.元素name
    
    document.onclick = function() {
        //alert(oText.value);
        
        alert( oForm.username.value );
        
    }
    
}
</script>
</head>

<body>
    <form id="form1">
        <input type="text" id="text1" name="username" value="" />
    </form>
</body>
</html>
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<script>
window.onload = function() {
    
    var oForm = document.getElementById('form1');
    var oBtn = document.getElementById('btn');
    
    //onchange : 当值发生改变的时候触发
    
    //text : 当光标离开元素的时候再去判断值是否发生了变化,如果发生了变化则触发onchange事件
    /*oForm.username.onchange = function() {
        alert('值变了');
    }*/
    
    /*oForm.sex[0].onchange = function() {
        alert(1);
    }*/
    
    for (var i=0; i<oForm.aihao.length; i++) {
        
        oForm.aihao[i].onchange = function() {
            
            //alert(1);
            
            if (this.checked) {
                alert('你选择了:' + this.value);
            } else {
                alert('你取消了:' + this.value);
            }
            
        }
        
    }
    
    oForm.city.onchange = function() {
        alert(this.value);
    }
    
}
</script>
</head>

<body>
    <form id="form1">
        <input type="text" name="username" />
        <input type="radio" name="sex" value="男" /><input type="radio" name="sex" value="女" checked /><input type="checkbox" name="aihao" value="电影" />电影
        <input type="checkbox" name="aihao" value="音乐" />音乐
        <input type="checkbox" name="aihao" value="体育" />体育
        
        <select name="city" value="">
            <option>请选择一个城市</option>
            <option value="北京">北京</option>
            <option value="上海" selected>上海</option>
            <option value="广州">广州</option>
            <option value="深圳">深圳</option>
        </select>
        
        <input type="button" value="按钮" id="btn" />
        <input type="submit" value="提交" />
    </form>
</body>
</html>
原文地址:https://www.cnblogs.com/nifengs/p/4972738.html