JavaScript String substring() 方法

substring()方法提取字符串的一部分并以新字符串的形式返回，而不修改原始字符串。

在开始(start)和结束(end)参数指定要提取字符串的一部分。

substring()从start提取字符，但不包括end。尤其是：

第一个字符的索引为0，第二个字符的索引为1，依此类推。

语法：

string.substring(start, end)

Example

var　str1　=　'Air Pollution is the introduction of chemicals into the atmosphere.39;;
var　str2　=　str1.substring(7);

All browsers fully support the substring() method：

Method
substring()	Is	Is	Is	Is	Is

Parameter	Description
start	(Required) The index of the first character to include in the returned substring
end	(Optional) The index of the first character to exclude from the returned substring. If omittedendIf so, substring() extracts to the end of the string.

Return value：	A new string containing the specified part of the given string
JavaScript version：	ECMAScript 1

The following examples use substring() to extract characters from the index4to9（10-1Extract characters from（

Example

var　str1　=　'Air Pollution is the introduction of chemicals into the atmosphere.39;;
var　str2　=　str1.substring(4,　10);