Why does the javascript-thinkphp file be uploaded after the onchange event is added to the input file in the?

I use the HTML5 FileReader implementation of the image upload preview function, the preview function, the submission of the form is reported "No files are uploaded" error, solve.
In the absence of a preview function can be successfully uploaded!!

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I use the HTML5 FileReader implementation of the image upload preview function, the preview function, the submission of the form is reported "No files are uploaded" error, solve.
In the absence of a preview function can be successfully uploaded!!

1-No one likes to read the source code.
2-Stickers are useless content, neither the form nor the submission of JS and no PHP-side receive processing
3-filereader is to provide a preview, use it and file can not upload a little relationship is not.

4- The biggest may be your form a few parameters , casually find a form upload file example to see, there is a very important attribute, I forgot how to write.
5-php End should print $_files (or $_file, forget), if there is a file is uploaded so that you can see, as for your last one of the reasons for guessing the wrong point of no use.

The form label addsenctype="multipart/form-data"

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