在闭包 scope 中保存变量

Question

I have the following:

var Save = $('th:first')[0];

$('th').click(function() {
    if (Save !== this) {
        Save = this;
        ...
    }
});

How do I put "Save" into a closure scope?

Answer 1

With jQuery, I tend to wrap the whole lot in a function, that passes in the jQuery object as $ , to avoid namespace clashes on that shorthand, as recommended by the jQuery documentation .

(function($) {
    // ....
})(jQuery);

Any variables within that scope, for instance your var Save , are then out of the global name scope, in a closure.

Answer 2

I don't really understand why you want to do what you're trying to do (or even what exactly you're trying to do...), but here are two solutions to what I think the question is about:

var Save = $('th:first')[0];

$('th').each(function() {
   var last = Save;
   $(this).click(function() {
      if (last !== this) {
         last = this;
          ...
      }
   });
});

and

var Save = $('th:first')[0];

$('th').data('Save', Save).click(function() {
    if ($(this).data('Save') !== this) {
        $(this).data('Save', this);
        ...
    }
});

** EDIT **

Of if what you want is just "shield" the variable Save , then

(function() {

var Save = $('th:first')[0];

$('th').click(function() {
    if (Save !== this) {
        Save = this;
        ...
    }
});

})();