1,parseInt(String str) 主要将首位为数字的字符串转换成数字,如果不是以数字开头,将返回NaN
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<script>
var num1="123abc";
var num2="abc123";
document.write("123abc转换结果为"+parseInt(num1)+"<br>");
document.write("abc123转换结果为"+parseInt(num2));
</script>
<body>
</body>
</html>
结果:
2,parseInt(String str) 主要将首位为数字的字符串转换成浮点型数字,如果不是以数字开头,将返回NaN
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<script>
var num="123.456789abc";
var num2="abc123.456789";
document.write("123.456.789abc转换结果为"+parseFloat(num)+"<br/>");
document.write("abc123.456789转换结果为"+parseFloat(num2));
</script>
<body>
</body>
</html>
结果:
3,isNaN() 用于检验某个值是否为NaN(not a number)是否为数字:false为数字,true为非数字
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<script>
var num = "123.456789abc";
var num2 = "abc123.456789";
document.write("123.456.789abc转换结果为" + isNaN(parseFloat(num)) + "<br/>");
document.write("abc123.456789转换结果为" + isNaN(parseFloat(num2)));
</script>
<body>
</body>
</html>
结果:
4,isFinite() 判断一个数是否为无穷大---如果出现1/0结果发生异常,返回false;
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<script>
document.write("10000000000000000除以0.0000000000000001是否为无穷大"+isFinite(10000000000000000/0.0000000000000001));
</script>
<body>
</body>
</html>
结果:
5,encodeURI() 用于返回一个URI字符编码后的结果-加密文件内容(类似于post的加密方式)
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<script>
document.write(encodeURI("http://127.0.0.1/save=?name=测试"));
</script>
<body>
</body>
</html>
结果:
6,decodeURI() 与encodeURI()作用相反,解密URI
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<script>
document.write(decodeURI("http://127.0.0.1/save=?name=%E6%B5%8B%E8%AF%95"));
</script>
<body>
</body>
</html>
结果: