一、charAt
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str1='abcdef';
//alert(str1.charAt(0));弹出a
alert(str1[0]);//不兼容IE6
</script>
</head>
<body>
</body>
</html>
二、charCodeAt
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str1='abcdef';
alert(str1.charCodeAt(0));//弹出a的码字
</script>
</head>
<body>
</body>
</html>
三、indexOf
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str='abcade';
alert(str.indexOf('a'));//找第一次出现的位置（弹出0） 没找到返回-1
//alert(str.indexOf('cad'));
</script>
</head>
<body>
</body>
</html>
四、lastIndexOf
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str='abcadea';
alert(str.lastIndexOf('a'));//找最后一个出现的位置（弹出6） 没找到返回-1
</script>
</head>
<body>
</body>
</html>
五、length
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str1='abc';
//var str2=new String('abc'); //包装类
alert(str1.length);//弹出3
</script>
</head>
<body>
</body>
</html>
六、match
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str='12,456 rt 77 99';
alert(str.match(/\d+/g));//选出数字 输出12,456,77,99
</script>
</head>
<body>
</body>
</html>
七、replace
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str='abca';
alert(str.replace('a','A'));//小写变大写（弹出Abca）
</script>
</head>
<body>
</body>
</html>
八、截取类（slice、substr 、substring）区别
slice 不取结束位置 把负数变为倒数第n个
substring 不取结束位置 把负数变为0，取全部字符
substr 取结束位置 把负数变为倒数第n个
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str='abcdef';
alert(str.substring(-1));//负数直接变为0，取所有字符
</script>
</head>
<body>
</body>
</html>
九、toLowerCase()大写变小写 toUpperCase()小写变大写
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>字符串</title>
<script type="text/javascript">
var str='GHHJHH';
alert(str.toLowerCase());//弹出ghhjhh
</script>
</head>
<body>
</body>
</html>
