JS to determine the file size and image size when uploading images

How to read the size of a picture:

First, the native input file control has a Files property, which is an array. The elements in the array have the following properties: Lastmodifieddate,name,size,type,webkitrelativepath,

　　

In this case, we can detect the size. (Size in this case is byte)

1 var fileData = file.files[0]; 2 var size = filedata.size;   // Note that the number of bytes read here is 3 var false ; 4 var maxSize = max_size; 5 maxSize = maxSize * 1024x768;   // Convert to bytes 6 isallow = size <= maxSize;

– Compatibility: IE9 cannot read input file.files this property.

How to get the width and height of a picture:

1. The actual width and height of the image can be obtained by instantiating the image object and loading src.

2. Compatibility: Use filter to handle picture size control under IE.

　　

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