revision:
The match() method matches a string against a regular expression. The match() method returns an array with the matches or it returns null if no match is found.
If the search value is a string, it is converted to a regular expression.
string.match(match)
Parameters:
match : required. The search value. A regular expression (or a string that will be converted to a regular expression).
<p>match() searches for a match in a string.</p>
<p>Do a search for "ain":</p>
<p id="demo"></p>
<script>
let text = "The rain in SPAIN stays mainly in the plain";
let result = text.match("ain");
document.getElementById("demo").innerHTML = result;
</script>
Do a search for "ain":
<div>
<p>Do a search for "ain":</p>
<p id="match-1"></p>
<p id="match-2"></p>
<p id="match-3"></p>
<p id="match-4"></p>
<p id="match-5"></p>
</div>
<script>
let text = "The rain in SPAIN stays mainly in the plain";
document.getElementById("match-1").innerHTML = "text : " + text;
let result = text.match("ain");
document.getElementById("match-2").innerHTML = "string - result : " + result;
let result1 = text.match(/ain/);
document.getElementById("match-3").innerHTML = "regular expression - result : " + result1;
let result2= text.match(/ain/g);
document.getElementById("match-4").innerHTML = "regular expression/g - result : " + result2;
let result3= text.match(/ain/gi);
document.getElementById("match-5").innerHTML = "regular expression/gi - result : " + result3;
</script>