if variable is string javascript

1if (typeof myVar === 'string'){
2    //I am indeed a string
3}

1if (typeof a_string === 'string') {
2    // this is a string
3}

1var booleanValue = true; 
2var numericalValue = 354;
3var stringValue = "This is a String";
4var stringObject = new String( "This is a String Object" );
5alert(typeof booleanValue) // displays "boolean"
6alert(typeof numericalValue) // displays "number"
7alert(typeof stringValue) // displays "string"
8alert(typeof stringObject) // displays "object"
9