Question

I have attached jsfiddle example here. I want to know difference between null and blank

My function is working fine but when I change blank to null in if condition it stop working.

Answer 1

1. you should probably change the condition to if('input[type=radio]:checked').val()) this way it will check both null and empty strings. but in this case i dont think you will ever get a null string.

2. dont use "!=" here because that might lead to some unpredictable behaviour use "!==".

3. null probably is like a null pointer when the object actually points to nothing
4. where as empty string points to an object which is ""