How to use substring method-JS Tutorial-php.cn

How to use substring method

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Release： 2021-04-20 10:41:51

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substring() is a built-in function in JavaScript that can be used to get a substring from a string and return a new substring based on the given parameters. Its usage syntax is such as "string.substring(indexA , [indexB])”.

How to use substring method

The operating environment of this article: Windows 7 system, Dell G3 computer, javascript version 1.8.5.

substring() is a built-in function in JavaScript, which is used to obtain substrings from strings. In this article, we will take a detailed look at the usage of substring.

Let’s take a look at the basic syntax of substring first

string.substring(indexA, [indexB])

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indexA - an integer between 0 and 1, less than the length of the string.

indexB (optional) - an integer between 0 and the length of the string.

The substring method returns a new substring based on the given parameters.

Let’s look at a specific example

The code is as follows

<!DOCTYPE html>
<html>
<head>
	<title></title>
</head>
<body>
<script type="text/javascript">

	// 将字符串作为变量
	var string = "sghxdysgcghd"; 
	a = string.substring(0, 4) 
	b = string.substring(1, 6) 
	c = string.substring(5) 
	d = string.substring(0) 

	// 输出新的字符串
	// 给定字符串的一部分
	document.write(a + "<br>"); 
	document.write(b + "<br>"); 
	document.write(c + "<br>"); 
	document.write(d + "<br>"); 					 
</script>
</body>
</html>

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The display effect on the browser is as follows:

How to use substring method

Indices always start with 0. If we still make the index negative, it will be considered zero and the index cannot be a decimal, if it is a decimal it will be converted to an integer smaller than it is.

Let’s take a look at the example

The code is as follows

<!DOCTYPE html>
<html>
<head>
  <title></title>
</head>
<body>
<script> 
  var string = "sghxdysgcghd"; 
  a = string.substring(-1) 
  b = string.substring(2.5) 
  c = string.substring(2.9) 
  document.write(a + "<br>"); 
  document.write(b + "<br>"); 
  document.write(c + "<br>"); 

</script>       
</body>
</html>

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The display effect on the browser is as follows

How to use substring method

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