The parseInt() method in JavaScript converts a string into a number. The method returns NaN if the value entered cannot be converted to a number.
Example
You can try to run the following code to convert a string into an integer −
<!DOCTYPE html>
<html>
<body>
<button onclick = "display()">Check</button>
<p id = "demo"></p>
<script>
function display() {
var val1 = parseInt("50") + "<br>";
var val2 = parseInt("52.40") + "<br>";
var val3 = parseInt(" 75 ") + "<br>";
var res = val1 + val2 + val3;
document.getElementById("demo").innerHTML = res;
}
</script>
</body>
</html>