<!DOCTYPE html>
<html>
<head>
<title>字符串对象</title>
</head>
<body>
<script type="text/javascript">
var mystr = "I love JavaScript";
var str_length = mystr.length;
document.write("mystr长度："+str_length+"<br>");
document.write("大写："+mystr.toUpperCase()+"<br>");
document.write("小写："+mystr.toLowerCase()+"<br>");
document.write("charAt："+mystr.charAt(0)+"<br>");
document.write("indexOf："+mystr.indexOf("J")+"<br>");
document.write("字符分割："+mystr.split(" ")+"<br>");
document.write("提取字符串："+ mystr.substring(3,6)+"<br>");
document.write("提取字符串："+ mystr.substr(3,6)+"<br>");
</script>
</body>
</html>
![这里写图片描述]()
