JavaScript入门篇
快速认识JavaScript 熟悉JavaScript基本语法 窗口交互方法 通过DOM进行网页元素的操作 学会如何编写JS代码 运用JavaScript去操作HTML元素和CSS样式
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>热身</title>
</head>
<body>
<p id="p1">我是第一段文字</p>
<p id="p2">我是第二段文字</p>
<script type="text/javascript">
document.write("hello");
document.getElementById("p1").style.color="blue";
</script>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb18030">
<title>插入js代码</title>
<script type="text/javascript">
document.write("开启JS之旅!");
</script>
</head>
<body>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>引用JS文件</title>
<script src="script.js"></script>
</head>
<body>
</body>
</html><!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JS代码的位置</title>
<script type="text/javascript">
document.write("I love");
</script>
</head>
<body>
<script type="text/javascript">
document.write("javascript");
</script>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>认识语句</title>
<script type="text/javascript">
document.write("Hello");
document.write("world");
</script>
</head>
<body>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>隐藏的注释</title>
<script type="text/javascript">
document.write("神奇的JS,快把我们隐藏了!"); // 快快把我变成单行注释
/*知道吗
JS可以实现很多动态效果
快来学习吧!*/
</script>
</head>
<body>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>变量</title>
<script type="text/javascript">
var mynum = 8;
</script>
</head>
<body>
</body>
</html><!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>判断语句</title>
<script type="text/javascript">
var score =80; //score变量存储成绩，初值为80
if(score>80)
{
document.write("很棒，成绩及格了。");
}
else
{
document.write("加油，成绩不及格。");
}
</script>
</head>
<body>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>函数调用</title>
<script type="text/javascript">
function contxt() //定义函数
{
alert("哈哈，调用函数了!");
}
</script>
</head>
<body>
<form>
<input type="button" value="点击我" onclick="contxt()" />
</form>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>document.write</title>
<script type="text/javascript">
var mystr="我是";
var mychar="JavaScript";
document.write(mychar+"<br>");
document.write(mystr+mychar+"的忠实粉丝!")
</script>
</head>
<body>
</body>
</html>
image.png
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>alert</title>
<script type="text/javascript">
function rec(){
var mychar="I love JavaScript";
alert(mychar)
}
</script>
</head>
<body>
<input name="button" type="button" onClick="rec()" value="点击我，弹出对话框" />
</body>
</html><!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>alert</title>
<script type="text/javascript">
function rec(){
var mychar="I love JavaScript";
alert(mychar)
}
</script>
</head>
<body>
<input name="button" type="button" onClick="rec()" value="点击我，弹出对话框" />
</body>
</html><!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>confirm</title>
<script type="text/javascript">
function rec(){
var mymessage= confirm("你是女士吗?");
if(mymessage==true)
{
document.write("你是女士!");
}
else
{
document.write("你是男士!");
}
}
</script>
</head>
<body>
<input name="button" type="button" onClick="rec()" value="点击我，弹出确认对话框" />
</body>
</html><!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>prompt</title>
<script type="text/javascript">
function rec(){
var score; //score变量，用来存储用户输入的成绩值。
score = prompt("你的分数是多少？");
if(score>=90)
{
document.write("你很棒!");
}
else if(score>=75)
{
document.write("不错吆!");
}
else if(score>=60)
{
document.write("要加油!");
}
else
{
document.write("要努力了!");
}
}
</script>
</head>
<body>
<input name="button" type="button" onClick="rec()" value="点击我，对成绩做评价!" />
</body>
</html><!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>window.open</title>
<script type="text/javascript">
function Wopen(){
window.open('http://www.123.com','_blank','height=600,width=400,top=100,left=0');
}
</script>
</head>
<body>
<input name="button" type="button" onClick="Wopen()" value="点击我，打开新窗口!" / >
</body>
</html>
image.png
语法：
window.open([URL], [窗口名称], [参数字符串])
_blank：在新窗口显示目标网页 _self：在当前窗口显示目标网页 _top：框架网页中在上部窗口中显示目标网页
window.close(); //关闭本窗口 <窗口对象>.close(); //关闭指定的窗口
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>close()</title>
<script type="text/javascript">
var mywin=window.open("http://www.123.com");
mywin.close();
</script>
</head>
<body>
</body>
</html><!DOCTYPE html>
<html>
<head>
<title> new document </title>
<meta http-equiv="Content-Type" content="text/html; charset=gbk"/>
<script type="text/javascript">
// 新窗口打开时弹出确认框，是否打开
function openWindow(){
var wep;
var op;
wep = confirm("是否打开新网页？");
if(wep==true)
{
op = prompt("默认网址为：","http://www.123.com/");
if(op!=null)
window.open(op,'_blank','width=400,height=500,menubar=no,toolbar=no');
}
else
alert("操作结束！！");
}
// 通过输入对话框，确定打开的网址，默认为 http：//www.imooc.com/
//打开的窗口要求，宽400像素，高500像素，无菜单栏、无工具栏。
</script>
</head>
<body>
<input type="button" value="新窗口打开网站" onclick="openWindow()" />
</body>
</html>HTML代码分解为DOM节点层次图:
通过ID获取元素 document.getElementById(“id”)
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>document.getElementById</title>
</head>
<body>
<p id="con">JavaScript</p>
<script type="text/javascript">
var mychar= ;
document.write("结果:"+mychar); //输出获取的P标签。
document.getElementById("con")
</script>
</body>
</html>innerHTML 属性 innerHTML 属性用于获取或替换 HTML 元素的内容。
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>innerHTML</title>
</head>
<body>
<h2 id="con">javascript</H2>
<p> JavaScript是一种基于对象、事件驱动的简单脚本语言，嵌入在HTML文档中，由浏览器负责解释和执行，在网页上产生动态的显示效果并实现与用户交互功能。</p>
<script type="text/javascript">
var mychar= ;
document.write("原标题:"+mychar.innerHTML+"<br>"); //输出原h2标签内容
document.getElementById("con")
document.write("修改后的标题:"+mychar.innerHTML); //输出修改后h2标签内容
mychar.innerHTML="Hello world";
</script>
</body>
</html>改变 HTML 样式
语法: Object.style.property=new style;
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>style样式</title>
</head>
<body>
<h2 id="con">I love JavaScript</H2>
<p> JavaScript使网页显示动态效果并实现与用户交互功能。</p>
<script type="text/javascript">
var mychar= document.getElementById("con");
mychar.style.color="red";
mychar.style.backgroundColor ="#ccc";
mychar.style.width="300px";
</script>
</body>
</html>显示和隐藏（display属性）
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>display</title>
<script type="text/javascript">
function hidetext()
{
var mychar = document.getElementById("con");
mychar.style.display="none";
}
function showtext()
{
var mychar = document.getElementById("con");
mychar.style.display="block";
}
</script>
</head>
<body>
<h1>JavaScript</h1>
<p id="con">做为一个Web开发师来说，如果你想提供漂亮的网页、令用户满意的上网体验，JavaScript是必不可少的工具。</p>
<form>
<input type="button" onclick="hidetext()" value="隐藏内容" />
<input type="button" onclick="showtext()" value="显示内容" />
</form>
</body>
</html>className 属性设置或返回元素的class 属性。
获取元素的class 属性
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>className属性</title>
<style>
body{ font-size:16px;}
.one{
border:1px solid #eee;
width:230px;
height:50px;
background:#ccc;
color:red;
}
.two{
border:1px solid #ccc;
width:230px;
height:50px;
background:#9CF;
color:blue;
}
</style>
</head>
<body>
<p id="p1" > JavaScript使网页显示动态效果并实现与用户交互功能。</p>
<input type="button" value="添加样式" onclick="add()"/>
<p id="p2" class="one">JavaScript使网页显示动态效果并实现与用户交互功能。</p>
<input type="button" value="更改外观" onclick="modify()"/>
<script type="text/javascript">
function add(){
var p1 = document.getElementById("p1");
p1.className = "one";
}
function modify(){
var p2 = document.getElementById("p2");
p2.className = "two";
}
</script>
</body>
</html><!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" Content="text/html; charset=utf-8" />
<title>javascript</title>
<style type="text/css">
body{font-size:12px;}
#txt{
height:400px;
width:600px;
border:#333 solid 1px;
padding:5px;}
p{
line-height:18px;
text-indent:2em;}
</style>
</head>
<body>
<h2 id="con">JavaScript课程</H2>
<div id="txt">
<h5>JavaScript为网页添加动态效果并实现与用户交互的功能。</h5>
<p>1. JavaScript入门篇，让不懂JS的你，快速了解JS。</p>
<p>2. JavaScript进阶篇，让你掌握JS的基础语法、函数、数组、事件、内置对象、BOM浏览器、DOM操作。</p>
<p>3. 学完以上两门基础课后，在深入学习JavaScript的变量作用域、事件、对象、运动、cookie、正则表达式、ajax等课程。</p>
</div>
<form>
<!--当点击相应按钮，执行相应操作，为按钮添加相应事件-->
<input type="button" value="改变颜色" >
<input type="button" value="改变宽高" >
<input type="button" value="隐藏内容" >
<input type="button" value="显示内容" >
<input type="button" value="取消设置" >
</form>
<script type="text/javascript">
//定义"改变颜色"的函数
obj.style.color
obj.style.backgroundColor
//定义"改变宽高"的函数
obj.style.width
obj.style.height
//定义"隐藏内容"的函数
obj.style.display="none";
//定义"显示内容"的函数
obj.style.display="block";
//定义"取消设置"的函数
confirm()
</script>
</body>
</html>本文参与 腾讯云自媒体分享计划，分享自作者个人站点/博客。
原始发表：2019.07.28 ，如有侵权请联系 cloudcommunity@tencent.com 删除
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