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How to remove leading and trailing white spaces from a given html string?

Posted by: admin November 30, 2017 Leave a comment

Questions:

I have the following html string. What would be sample code in JavaScript to remove leading and trailing white spaces from this string?

<p>&nbsp;&nbsp;</p>
<div>&nbsp;</div>
Trimming using JavaScript<br />
<br />
<br />
<br />
all leading and trailing white spaces
<p>&nbsp;&nbsp;</p>
<div>&nbsp;</div>
Answers:

See the String method trim()https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/Trim

var myString = '  bunch    of <br> string data with<p>trailing</p> and leading space   ';
myString = myString.trim();
// or myString = String.trim(myString);

Edit

As noted in other comments, it is possible to use the regex approach. The trim method is effectively just an alias for a regex:

if(!String.prototype.trim) {  
  String.prototype.trim = function () {  
    return this.replace(/^\s+|\s+$/g,'');  
  };  
} 

… this will inject the method into the native prototype for those browsers who are still swimming in the shallow end of the pool.

Questions:
Answers:
var str = "  my awesome string   "
str.trim();    

for old browsers, use regex

str = str.replace(/^[ ]+|[ ]+$/g,'')
//str = "my awesome string" 

Questions:
Answers:
string.replace(/^\s+|\s+$/g, "");

Questions:
Answers:

If you’re working with a multiline string, like a code file:

<html>
    <title>test</title>
    <body>
        <h1>test</h1>
    </body>
</html>

And want to replace all leading lines, to get this result:

<html>
    <title>test</title>
    <body>
        <h1>test</h1>
    </body>
</html>

You must add the multiline flag to your regex, ^ and $ match line by line:

string.replace(/^\s+|\s+$/gm, '');

Relevant quote from docs:

The “m” flag indicates that a multiline input string should be treated as multiple lines. For example, if “m” is used, “^” and “$” change from matching at only the start or end of the entire string to the start or end of any line within the string.

Questions:
Answers:
var trim = your_string.replace(/^\s+|\s+$/g, '');