0514JS操作document对象、事件、（this）

var duixiang = document.getElementById("first");
console.log(duixiang);

var duixiang = document.getElementsByClassName("second");
var duixiang = document.getElementsByClassName("second")[0];
console.log(duixiang);

var duixiang = document.getElementsByName("third");
var duixiang = document.getElementsByName("third")[0];
console.log(duixiang);

var duixiang = document.getElementsByTagName("div");
var duixiang = document.getElementsByTagName("div")[0];
console.log(duixiang);

var duixiang = document.querySelector("#first");
console.log(duixiang);

var duixiang = document.querySelector(".second");
console.log(duixiang);

var duixiang = document.querySelectorAll(".second")[0];
var duixiang = document.querySelectorAll(".second");
console.log(duixiang);

var biaodan = document.getElementsByTagName("input")[0];
biaodan.value = "给value加属性值";

var biaodan = document.getElementsByTagName("input")[0];
biaodan.value = "给value加属性值";
var feibiaodan = document.getElementById("first");
feibiaodan.innerText = "innerText<br />不可以解析标签"

#first{
    width: 200px;
    height: 200px;
    background-color: green;
    border-radius: 10px;
    color: blue;
    text-align: center;
    line-height: 200px;
}
var yangshi = document.querySelector("#first");
yangshi.style.width = "300px";
yangshi.style.height = "300px";
yangshi.style.backgroundColor = "yellow";
yangshi.style.marginLeft = "100px";

|----改变标签的名称,标签直接变为另一个名称的样式：className=""

.second{
    width: 200px;
    height: 200px;
    background-color: green;
    border-radius: 10px;
    color: blue;
    text-align: center;
    line-height: 200px;
    float: left;
}
.fourth{
    width: 300px;
    height: 300px;
    background-color: yellow;
    border-radius: 100px;
    color: blue;
    text-align: center;
    line-height: 200px;
    margin-top: 100px;
    float: left;
}
var yangshi = document.querySelector(".second");
yangshi.className = "fourth";

 

|--操作属性
|----通过属性名获取属性：getAttribute("属性名");

<div class="second" name="third" ></div>
var huoqu = document.querySelector(".second");
console.log(huoqu.getAttribute("name"))

|----改变属性名和属性值：setAttribute("属性名"，"属性值");

<input type="checkbox" name="" id="" value="" />张店
<input type="checkbox" name="" id="" value="" />临淄
<input type="checkbox" name="" id="" value="" />周村
<input type="checkbox" name="" id="" value="" />全选
var gaibian = document.getElementsByTagName("input")[1];
gaibian.setAttribute("checked","checked")

|----通过删除属性名来删除标签的属性：removeAttribute("属性名");

<div id="" style="" aa="" bb=""></div>
var shanchu = document.getElementsByTagName("div")[0];
shanchu.removeAttribute("aa");
console.log(shanchu);

|事件
|-常用事件
|--点击事件:onclick
|--鼠标按下事件：onmousedown
|--鼠标弹起事件：onmouseup
|--内容改变事件：onchange
|--失去焦点事件：onblur
|--得到焦点事件：onfocus
|--鼠标移入事件：onmouseover
|--鼠标移出事件：onmouseout
|-给元素加事件的方法
|--在标签元素内部添加事件
|----事件调用函数：<标签名    事件名="函数名()"></标签名>
|--通过循环给多个元素添加事件
|----获取对象元素，通过时间给元素添加函数：对象值.事件名=匿名函数(one[i].onclick = function(){})

|this关键词

|-先获取对象attr，不可是集合

|-此时this.就是attr.