function count(str, find) {
return (str.split(find)).length - 1;
}
count("Good", "o"); // 2
var temp = "This is a string.";
var count = (temp.match(/is/g) || []).length;
console.log(count);
Output: 2
Explaination : The g in the regular expression (short for global) says to search the whole string rather than just find the first occurrence. This matches 'is' twice.
console.log(("str1,str2,str3,str4".match(/,/g) || []).length); //logs 3
console.log(("str1,str2,str3,str4".match(new RegExp("str", "g")) || []).length); //logs 4