小项目----4

2022-06-16 16:32:18 作者：互联网
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
    注册：<br/>
    <form name="form"  meethod="post" action="#">
        姓名：<input name="username" type="text">*
        年龄：<input name="age" type="text">*
        <select name="sel_city">
            <option value="0">--请选择城市--</option>
            <option value="北京">北京</option>
            <option value="上海">上海</option>
            <option value="广州">广州</option>
        </select>
        <input name="city" size="12" readonly="readonly" type="text">*
        <input type="submit" name="btn" id="btn" value="提交">
    </form>
    
    
<script>
    
    form.username.onmouseover = function(){
        this.focus();
        this.select();
    }
    form.age.onmouseover = function(){
        this.focus();
        this.select();
    }
    form.age.onkeydown = function(ev){
        oEven = ev || even;
        if(oEven.keyCode<48 || oEven.keyCode>57){
            return false;
        }
    }
    form.sel_city.onchange = function(){
        if(this.value==0){
            alert('请选择一个城市');
        }else{
            form.city.value = form.sel_city.value;
        }
    }
    form.onsubmit = function(){
        if(form.username.value==''){
            alert('姓名为填写，无法提交');
            form.username.focus();
            return false;
        }else if(form.age.value==''){
            alert('年龄未填写，不能提交');
            form.age.focus();
            return false;
        }else if(form.city.value=='' || form.city.value=='请选择城市'){
            alert('城市未提交，不能提交');
            form.sel_city.focus();
            return false;
        }
    }
    form.city.onmouseover = function(){
        if(this.value==''){
            this.value = '请选择城市';
        }
    }
    
</script>
</body>
</html>
标签：function,city,false,form,项目,focus,value,----
来源： https://www.cnblogs.com/wgqy/p/16382416.html