check if variable is undentified javascript code example
Example 1: javascript if undefined
if(typeof comment === 'undefined') {
alert('Variable "comment" is undefined.');
} else if(comment === null){
alert('Variable "comment" is null.');
}
Example 2: undefined value check in javascript
function divisors(integer) {
let i, flag = true;
let arr=[];
for(i = 2; i <= integer - 1; i++) {
if (integer % i == 0) {
flag = false;
arr.push(i)
}
}
if (flag == true)
console.log(integer + " is prime");
else
console.log(arr)
}
console.log(divisors(15))