Creation and manipulation of arrays in JavaScript
How to create an array
##1. Use the new keyword and Array() to create an array
##var arr = new Array(); //Create an empty array
var arr = new Array("zhou gensheng" , "male" , 30); //Create an array and initialize the elements of the array
<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>php.cn</title> <script> //創(chuàng)建一個沒有任何元素的數(shù)組 var arr = new Array(); //增加數(shù)組元素 arr[0] = "張三"; arr[1] = "男"; arr[2] = 25; arr[3] = "安徽"; document.write(arr); </script> </head> <body> </body> </html>
2. Use [] to create
## square brackets [ ], use commas in English to separate multiple values.
<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>php.cn</title> <script> //使用[]方式創(chuàng)建一個數(shù)組 var arr = ["張三","男",25,"安徽"]; document.write(arr); </script> </head> <body> </body> </html>
Array operations
- Modify element: Modify the value of an element with an existing subscript (reassign a value). For example: arr[2] = 26;
- Add element: add an element with a non-existent subscript.
- Delete elements: Using the keyword delete, you can only delete the value of the element, while the subscript is still there.
