Definition and Usage
定义与用法

The substring() method extracts the characters in a string between two specified indices.
substring()方法用于取出字符串中特定位置间的字符

Syntax
语法

stringObject.substring(start,stop)

Tips and Notes
注意

Note: To extract characters from the end of the string, use a negative start number.
注意：要从字符的尾部开始取字符，用负数做为起始字符。

Note: The start index starts at 0.
注意：第一个字符的位置为0

Note: If the stop parameter is omitted, this method extracts to the end of the string.
注意：如果为指定结束位置，默认将选取到字符串结束。

Example
实例

In this example we will use substring() to extract some characters from a string:
在本例中，我们将演示substring()从字符串中选取一些字符：

<script type="text/javascript">

var str="Hello world!"
document.write(str.substring(3))

</script>

The output of the code above will be:
输出结果为：

lo world!

Example
实例

In this example we will use substring() to extract some characters from a string:
在本例中，我们将用substring()从字符串中选取一些字符：

<script type="text/javascript">

var str="Hello world!"
document.write(str.substring(3,7))

</script>

The output of the code above will be:
输出结果为：

lo w

Try-It-Yourself Demos
互动演练

substring()
How to use substring() to extract some characters from a string.
如何用substring()从字符串中选取一些字符

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