title: regex for multiple option
body: <p>I need to write a regex expression to use with JS .match() function. The objective is to check a string with multiple alternatives. For example, I want to return true in below code if mystr contains word1 or word2 or word3</p>
  
  <pre><code>mystr1 = "this_is_my_test string_containing_word2_where_i_will_perform_search";
  mystr2 = "this_is_my_test string_where_i_will_perform_search";
  myregex = xxxxxx; // I want help regarding this line so that 
  if(mystr1.match(myregex)) return true; //should return true
  if(mystr2.match(myregex)) return true; //should NOT return true
  </code></pre>
  
  <p>Any help please?</p>