• js和dom


        1. 写页面是觉得丑
            float,clear:both,margin,padding
            position:
                left:
            
            网上找模板
            HTML模板,BootStrap
        2. 背景图片
            
    HTML
        一大堆的标签:块级、行内
        
    CSS
        position
        background
        text-align
        margin
        padding
        font-size
        z-index
        over-flow
        :hover
        opacity
        float (clear:both)
        line-height
        border
        color
        display
        
        补充:页面布局
              主站—
                    <div class='pg-header'>
                           <div style='980px;margin:0 auto;'>
                               内容自动居中
                           </div>
                    
                    </div>
                    <div  class='pg-content'></div>
                    <div  class='pg-footer'></div>
              后台管理布局:
                position:
                    fiexd    -- 永远固定在窗口的某个位置
                    relative -- 单独无意义
                    absolute -- 第一次定位,可以在指定位置,滚轮滚动时,不在了。。。。
                    
                a.
                    左侧菜单跟随滚动条
                b.
                    左侧以及上不不动   ******


    JavaScript


        6、for循环
        
            for(var item in [11,22,33]){
                console.log(item);
                continue;
            }
            
            var arra = [11,22,32,3]
            for(var i=0;i<arra.lenght;i=i+1){
                break;
            }
            
            while(条件){
            
            
            }
        7、条件语句
        
            if(){
            
            }else if(){
            
            }else{
            
            }
            
            ==
            ===
            
            name='3';
            
       
            switch(name){
                case '1':
                    age = 123;
                    break;
                case '2':
                    age = 456;
                    break;
                default :
                    age = 777;
            }
            
        8. 函数
            function func(arg){
            
                return arg+1
            }
            var result = func(1)
            console.log(result);
            
            普通函数:
                function func(){
                    
                }
            匿名函数:
                
                function func(arg){
                
                    return arg+1
                }
                
                setInterval("func()", 5000);
                
                setInterval(function(){
                    console.log(123);
                
                },5000)
                
            自执行函数(创建函数并且自动执行):
                function func(arg){
                    console.log(arg);
                }
                // func(1)
                
                (function(arg){
                    console.log(arg);
                })(1)
        9、序列化
            JSON.stringify()   将对象转换为字符串
            JSON.parse()       将字符串转换为对象类型
            
        10、转义
            客户端(cookie)   =》 服务器端
            将数据经过转义后,保存在cookie
            
        11、eval
            python:
                val = eval(表达式)
                      exec(执行代码)
            JavaScript:
                eval
        12、时间
            Date类
            
            var d = new Date()
            
            d.getXXX  获取
            d.setXXX  设置
            
        13、作用域
            ================================ 1. 以函数作为作用域 (let)================================
            
            其他语言: 以代码块作为作用域
                        public void Func(){
                            if(1==1){
                                string name = 'Java';
                                
                            }
                            console.writeline(name);
                            
                        }
                        Func()
                        // 报错
                        
            Python:   以函数作为作用域
                        情况一:
                            def func():
                                if 1==1:
                                    name = 'alex'
                                print(name)
                                
                            func()
                            // 成功
                        情况二:
                            def func():
                                if 1==1:
                                    name = 'alex'
                                print(name)
                                
                            func()
                            print(name)
                            // 报错
                    
            JavaScript:  以函数作为作用域
            
                        function func(){
                            if(1==1){
                                var name = 'alex';
                            }
                            console.log(name);
                        }
                        func()
            
            ================================ 2. 函数的作用域在函数未被调用之前,已经创建 ================================
            
            function func(){
                if(1==1){
                    var name = 'alex';
                }
                console.log(name);
            }
            
            ================= 3. 函数的作用域存在作用域链,并且也是在被调用之前创建 ==================
            示例一:
                xo = "alex";
                
                function func(){
                    // var xo = 'eric';
                    function inner(){
                        // var xo = 'tony';
                        console.log(xo);
                    }
                    
                    inner()
                }
                
                func()
            
            示例二:
                xo = "alex";
                
                function func(){
                    var xo = 'eric';
                    function inner(){
                        
                        console.log(xo);
                    }
                    
                    return inner;
                }
                
                var ret = func()
                ret()
            
            
            
            示例三:
                xo = "alex";
                
                function func(){
                    var xo = 'eric';
                    function inner(){
                        
                        console.log(xo);
                    }
                    var xo = 'tony';
                    
                    return inner;
                }
                
                var ret = func()
                ret()
            
            ================= 4. 函数内局部变量 声明提前 ==================
            
            function func(){
                console.log(xxoo);
            }
            
            func();
            // 程序直接报错
            
            function func(){
                console.log(xxoo);
                var xxoo = 'alex';
            }
            解释过程中:var xxoo;
            
            func();
            // undefined
            
        14、JavaScript面向对象
            
            JavaScript面向对象
                function foo(){
                    var xo = 'alex';
                }
                
                foo()
                
                
                
                function Foo(n){
                    this.name = n;
                    this.sayName = function(){
                        console.log(this.name);
                    }
                }
                
                var obj1 = new Foo('we');
                obj1.name
                obj1.sayName()
                
                
                var obj2 = new Foo('wee');
                obj2.name
                obj2.sayName()
                ==============》
                    a. this代指对象(python self)
                    b. 创建对象时, new 函数()
            
            
            Python的面向对象:
                class Foo:
                    def __init__(self,name):
                        self.name = name
                        
                    def sayName(self):
                        print(self.name)
                        
                obj1 = Foo('we')

                obj2 = Foo('wee')
            
           
            原型:
            
                function Foo(n){
                    this.name = n;
                }
                # Foo的原型
                Foo.prototype = {
                    'sayName': function(){
                        console.log(this.name)
                    }
                }
                
            
                obj1 = new Foo('we');
                obj1.sayName()
                
                obj2 = new Foo('wee');


    DOM
        查找
            直接查找
                var obj = document.getElementById('i1')
            间接查找
                文件内容操作:
                    innerText    仅文本
                    innerHTML    全内容
                    value
                        input    value获取当前标签中的值
                        select   获取选中的value值(selectedIndex)
                        textarea value获取当前标签中的值
                    
                    搜索框的示例
        操作:      
                样式操作:
                    className
                    classList
                        classList.add
                        classList.remove
                       
                       
                    obj.style.fontSize = '16px';
                    obj.style.backgroundColor = 'red';
                    obj.style.color = "red"
                    
                    
                属性操作:
                    attributes
                    getAttribute
                    removeAttribute
                    
                创建标签,并添加到HTML中:
                    a. 字符串形式
                    
                    b. 对象的方式
                        document.createElement('div')
                    
                    
                提交表单
                    任何标签通过DOM都可提交表单
                    
                    document.geElementById('form').submit()
                
                其他:
                    console.log()
                    alert
                    var v = confirm(信息)  v:true false
                    
                    location.href
                    location.href = ""  # 重定向,跳转
                    location.reload()   # 页面刷新
                    location.href = location.href   < === > location.reload()
                    
                    
                    var o1 = setInterval(function(){}, 5000)
                    clearInterval(o1);
                    
                    var o2 = setTimeout(function(){}, 50000);
                    clearTimeout(o2);
                    
                    var obj = setInterval(function(){
                        
                    }, 5000)
                    
                    clearInterval(obj);
            
        事件:
            onclick,onblur,onfocus
            
            行为  样式  结构 相分离的页面?
            js    css   html  
            
            绑定事件两种方式:
                a. 直接标签绑定 onclick='xxx()'  onfocus
                b. 先获取Dom对象,然后进行绑定
                    document.getElementById('xx').onclick
                    document.getElementById('xx').onfocus
                    
            this,当前触发事件的标签
                a. 第一种绑定方式
                    <input id='i1' type='button' onclick='ClickOn(this)'>
                    
                    function ClickOn(self){
                        // self 当前点击的标签
                        
                    }
                b. 第二种绑定方式
                    <input id='i1' type='button' >
                    document.getElementById('i1').onclick = function(){
                    
                        // this 代指当前点击的标签
                    }
                
                    
            作用域示例:
                    var myTrs = document.getElementsByTagName("tr");
                    var len = myTrs.length;
                    for(var i=0;i<len;i++){
                        // i=0,i=1,i=2
                        myTrs[i].onmouseover = function(){
                             this.style.backgroundColor = "red";
                        };

                    }

    A wise man thinks all that he says, a fool says all that he thinks.
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  • 原文地址:https://www.cnblogs.com/BernieChen/p/6093597.html
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