If I have a declaration as follows:
var j;
does j==null until I set it equal to something?
If I have a declaration as follows: var j; does j==null until I set
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If I have a declaration as follows:
var j;
does j==null until I set it equal to something?
No, it has the default value of
undefinedBut if want to use the
!jcondition, it will work with both the values (i.e. undefined or null)Note that
(j==null)istrue, but(j===null)isfalse… JavaScript have “falsy” values and sometimes unexpected rules to convert values, plus fancy===operator to compare value and type at the same time.