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@jokester
Created October 31, 2015 01:11
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只能由特定code使用的, 只定義一次的變數
document.getElementById('testbutton').onclick = (function () {
// 這邊的t和a只會定義一次
var t = Math.tan(Math.PI * 0.2);
var a;
// 下面的function每次實行時都會重復使用上面的t和a
// 其他code看不到上面的t和a
return function() {
var i = 0;
for(; i < 1000; i ++){
a = i / t;
//do something
}
};
})();
(function() {
var t = Math.tan(Math.PI * 0.2);
var a;
document.getElementById('testbutton').onclick = function () {
var i = 0;
for(; i < 1000; i ++){
a = i / t;
//do something
};
};
})();
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