Question

$('#id').val() = $.cookie("name"); – not works, nothing changes

document.getElementById('id').value = $.cookie("name"); – works fine

Why?

Answer 1

You are not directly accessing the elements value. The left hand side of your expression is a getter which evaluates to a literal. So the expression is comparable to something like 5 = 10, which obviously cant work

$('#id').val() = $.cookie("name");

val() is overloaded, and by giving it an argument you can reassign

$('#id').val($.cookie("name"));