Keep it simple! Say what you cannot have, rather than what you can have :]
As mentioned above, URLs can be quite complex, especially after the '?', and not all of them start with a 'www.' e.g. maps.bing.com/something?key=!"£$%^*[]&lat=65&lon&lon=20
So, rather than have a complex regex that wont meet all edge cases, and will be hard to maintain, how about this much simpler one, which works well for me in practise.
Match
http[s]:// [anything but a space]+
www. [anything but a space]+
Where 'anything' is [^'"\s] ... basically a
greedy match, carrying on to you meet a space, quote, angle bracket, or end of line
Also:
Remember to check that it is not already in URL format, e.g. the text contains href="..." or src="..."
Add ref=nofollow [if appropriate]
This solution isn't as "good" as the libraries mentioned above, but is much simpler, and works well in practise.
if html.match[ /[href]|[src]/i ]] {
return html; // text already has a hyper link in it
}
html = html.replace[
/\b[https?:\/\/[^\s\[\]\'\"\]+]/ig,
"$1"
];
html = html.replace[
/\s[www\.[^\s\[\]\'\"\]+]/ig,
"$1"
];
html = html.replace[
/^[www\.[^\s\[\]\'\"\]+]/ig,
"$1"
];
return html;
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Given an plane URL and the task is to replace the plain URLs into the links. This problem can be solve with the help of Regular
Expressions.
Approach 1:
- RegExp – Which looks for the URL in the provided text.
- This RegExp parse the URL and put the address to the $1 variable.
- After getting the URL in text, it replace it with element and set its href and other attributes.
Example 1: This example implements the above approach.
html
How to replace plain URL with
link using JavaScript ?
GeeksForGeeks
click here
var up = document.getElementById['GFG_UP'];
var down = document.getElementById['GFG_DOWN'];
up.innerHTML = "Click on the button to replace "
+ "plain URLs with links." + text;
function rep[text] {
// Put the URL to variable $1 after visiting the URL
var Rexp =
/[[http|https|ftp]:\/\/[\w?=&.\/-;#~%-]+[?![\w\s?&.\/;#~%"=-]*>]]/g;
// Replace the RegExp content by HTML element
return text.replace[Rexp,
"Link to URL"];
}
function GFG_Fun[] {
down.innerHTML = rep[text];
}
Output:
- Before clicking on the button:
- After clicking on the button:
Approach 2:
- RegExp – Which looks for the URL in the provided text and also finds the domain name of the URL.
- After getting the URL in text, it replace it with a element and set its href and other attributes. It also replaces the link text by domain name.
Example 2: This example implements the above
approach.
html
How to replace plain URL with
link using JavaScript ?
GeeksForGeeks
click here
var up = document.getElementById['GFG_UP'];
var down = document.getElementById['GFG_DOWN'];
up.innerHTML = "Click on the button to replace "
+ "plain URLs with links." + text;
function rep[text] {
// Put the URL to variable $1 and Domain name
// to $3 after visiting the URL
var Rexp =
/[\b[https?|ftp|file]:\/\/[[-A-Z0-9+&@#%?=~_|!:,.;]*][[-A-Z0-9+&@#%?\/=~_|!:,.;]*][-A-Z0-9+&@#\/%=~_|]]/ig;
// Replacing the RegExp content by HTML element
return text.replace[Rexp,
"$3"];
}
function GFG_Fun[] {
down.innerHTML = rep[text];
}
Output:
- Before clicking on the button:
- After clicking on the button: