{Javascript} Difference in calling method on object or pass

// create object constructor
function Foo(prop1, prop2) {
    this.prop1 = prop1;
    this.prop2 = prop2;
    // create object method PrintObjectPropertyM
    // and retreive property value
    // * there is M at the end of property to distinguish
    // method/function name

    // how can I add placeholder/argument in method and then
    // call method on object with provided argument (here prop1 or prop2)
    this.printObjectPropertyM = function() {
        console.log(this.prop1);
    };
}

// instantiate new object Bar of Foo type
var Bar = new Foo("prop1val", "prop2val");

// create function which print object property and take object as an argument
var printObjectProperty = function(object) {
    console.log(object.prop1);
};

// call printObjectProperty with Bar object as an argument
printObjectProperty(Bar); // logs prop1var in console

// call Bar method printObjectPropertyM
Bar.printObjectPropertyM(); // logs prop1val in console