While working in my current project, I re-learned this hard way. And I don’t want to make same mistake again, hence noting it here. Many a times you remember something better when noted somewhere.
I had created a javascript that was similar as below:
1: function Type1(){
2: _type = "type1";
3: this.show = function() { alert(_type); }
4: }
5: function Type2(){
6: _type = "type2";
7: this.show = function() { alert(_type); }
8: }
9: o1 = new Type1();
10: o2 = new Type2();
11: o1.show();
12: o2.show();
And me being ignorant about what I have written, was expecting to see two alerts once with “type1” and another with “type2”.
Case that I had was more complex , hence I took more time to understand the problem, and then note that I haven’t have “var”! The code should be as:
1: function Type1(){
2: var _type = "type1";
3: this.show = function() { alert(_type); }
4: }
5: function Type2(){
6: var _type = "type2";
7: this.show = function() { alert(_type); }
8: }
9: o1 = new Type1();
10: o2 = new Type2();
11: o1.show();
12: o2.show();
Note and Remember, “var” defines the scope of variable as local!
