js check string for number code example

Example 1: javascript is variable a string

if (typeof myVar === 'string'){
    //I am indeed a string
}

Example 2: js string have number js

var hasNumber = /\d/;   
      hasNumber.test("ABC33SDF");  //true
      hasNumber.test("ABCSDF");  //false

Example 3: how to check if a string is an integer javascript

isNaN(num)         // returns true if the variable does NOT contain a valid number