VAR is not necessarily the boundary between the global variables and local variables used to define local variables for JScript: All variables outside the procedure body (including method function, object o ={}) regardless of whether you have a var reserved word, he is a global variable the object in the procedure body (including the method function () {}, Object o={}) plus the VAR reserved word is a local variable, without the addition of the VAR reserved word is the global variable : As long as the process body outside, is a global variable, in the process body Nega var is a local variable does not add to the global variable JS global scope should be in the scope of looking at, not necessarily the same page, for example, in an IFRAME can not call embedded his page JS
JS in the definition of variable plus var and no var difference?
