how to check if undefined in javascript code example

Example 1: js if not undefined

if (typeof myVar !== "undefined") {
    console.log("myVar is DEFINED");
}

Example 2: javascript check undefined

if(myVar === null) {
	console.log("Element is undefined");
}

Example 3: undefined javascript check

if(undefinedElement === null) {
	console.log("Element is undefined");
}