使用 encodeURIComponent 將字串傳換為 URI 要將空白換成+

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For application/x-www-form-urlencoded (POST), spaces are to be replaced by '+', so one may wish to follow a encodeURIComponent replacement with an additional replacement of "%20" with "+".
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Reference:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent
http://www.w3.org/TR/html401/interact/forms.html#form-content-type