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JavaScript,可以嵌套在静态页面中添加一些动态语言.
JavaScript是开发web脚本语言,但也被用到了很多非浏览器环境中,比如node平台
JS可以嵌套在静态页面中可以给静态页面添加一些动态效果(脚本语言),不同浏览器厂商(在浏览器中都有内置解析器解析JS语法)
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<body></body>
</html>
<script>//警告框alert("hello world");//提示框prompt("姑娘你的名字");prompt("姑娘你的年龄",18);
</script>
<script>console.log("hello world");console.log(123);console.log(undefined);console.log(null);console.log(typeof 123);
</script>
<script>var num;num=3;console.log(num);var a=100;var b=200;var c=300;console.log(a,b,c);
</script>
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<body></body>
</html>
<script>function fun(){console.log("白毛浮绿水");console.log("红掌拨清波");}fun();function sum(a,b){console.log(a+b);}sum(100,200);sum("大华","小华");
</script>
JS函数当中没有重载的问题,永远是后者覆盖前者.
return后面的语句不再执行
return可以在函数体汇总将计算完结果返回,在函数体中使用
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<body></body>
</html>
<script>function fun(){console.log("白毛浮绿水");console.log("红掌拨清波");}fun();function sum(a,b){console.log(a+b);}sum(100,200);sum("大华","小华");</script>
pop:是数组的一个方法,主要的作用是可以在数组尾巴处移除一项元素,
pop方法有返回数值,返回的是移除掉的那项元素.
push:是数组方法,主要的作用是可以向数组添加一个或多个元素.
reverse:数组元素进行倒置
indexof
join,concat
slice切割数组
splice
Dom
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<body></body>
</html>
<script>console.log(document);console.log(document.documentElement);console.log(document.head);console.log(document.body);console.log(document.title);
</script>
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<body><div>我是表单元素:<input type="text" value="我是表单元素" id="cur"><a href="http:\\www.baidu.com" id="box">我是超链接</a></div>
</body>
</html>
<script>var cur = document.getElementById('cur');console.log(cur);console.log(cur.value);cur.value = '我是修改后的表单元素';var box=document.getElementById('box');console.log(box.innerHTML);box.innerHTML = '我是修改后的超链接';
</script>
事件:事件是由用户触发