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

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

Any help please?