function case_insensitive_search(str, search_str)  
  {  
    var result= str.search(new RegExp(search_str, "i"));  
    
    if (result>0)  
    return 'Matched';  
    else  
    return 'Not Matched';    
   }  
  
console.log(case_insensitive_search('JavaScript Exercises', 'exercises'));  
  
console.log(case_insensitive_search('JavaScript Exercises', 'Exercises'));  
  
console.log(case_insensitive_search('JavaScript Exercises', 'Exercisess'));