javascript checking undefined code example
Example 1: js if not undefined
if (typeof myVar !== "undefined") {
console.log("myVar is DEFINED");
}
Example 2: javascript if undefined
if(typeof comment === 'undefined') {
alert('Variable "comment" is undefined.');
} else if(comment === null){
alert('Variable "comment" is null.');
}
Example 3: test if is undefined javascript
let id;
if(typeof id === 'undefined') {
console.log("id is undefined...");
}
Example 4: javascript check number against undefined
javascript check number against undefined