javascript set condition on string null or empty 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: empty string in javascript

var s; // undefined
var s = ""; // ""
s.length // 0