gistfile1.js

var test1 = new testModel1(1); // creates a new instance with the id 1
var test2 = new testModel1(2); // creates a new instance with the id 2

test1.p('name', 'test'); // sets this.properties.name to 'test'
test2.p('name', 'shit'); // sets this.properties.name to 'shit'
console.dir(test1.id);
console.dir(test2.id);
console.dir(test1.p('name'));  // returns this.properties.name

output

1
2
'shit'