how to check string is undefinedin javscript code example

Example 1: javascript check if undefined or null or empty string

// simple check do the job
if (myString) {
 // comes here either myString is not null,
 // or myString is not undefined,
 // or myString is not '' (empty).
}

Example 2: undefined javascript check

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