The common space character is encoded as %20 as you noted yourself. A bit of explaining as to what that %2520 is : 照片的尺寸是以英寸为单位，1英寸=2.54cm ，通常x寸是指照片长的一边的英寸长度。 身份证、体检表等多采用小一寸22×32mm， 第二代身份证 26mm×32mm，普通一寸相.
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If you look at rfc 3986 appendix a, you will see that space is simply not mentioned anywhere in the grammar for defining a url. The % character is encoded as %25. Since it's not mentioned anywhere in.
As the aforementioned rfc does not include any reference of encoding spaces as +, i guess using %20 is the way to go today.
