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    Write a JavaScript function to check whether a given value is a valid URL or not

    Posted on 2021-03-21

    Write a JavaScript function to check whether a given value is a valid URL or not. There is a simple way to validate if an URL is valid in Javascript, no messy Regex needed. 

    <!DOCTYPE html>
    <html>
    <head>
      <title>URL Validation</title>
    </head>
    <body>
    
    <script type="text/javascript">
    	function is_url(str)
    	{
    	  regexp =  /^(?:(?:https?|ftp):\/\/)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,})))(?::\d{2,5})?(?:\/\S*)?$/;
    	        if (regexp.test(str))
    	        {
    	          return 'It is a valid URL.';
    	        }
    	        else
    	        {
    	          return 'Not valid URL';
    	        }
    	}
    
    	alert(is_url("http://www.rajlama.com.np"));
    </script>
    </body>
    </html>
    

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