What should I do if the php verification code does not display characters?

The solution to the problem that the php verification code does not display characters: 1. Open the gd library; 2. Directly request the URL of the image; 3. Change the file to utf-8 encoding without BOM; 4. Add ob_clean() Just function.

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

What should I do if the php verification code does not display characters? ?

The verification code in php does not display the problem

1. First, you must make sure that your gd is turned on and there is no problem with your server

2. When your verification code does not display, you can directly request the URL of your image

Syntax error:

Logicalerror:

At this time,, if a syntax error occurs, the page will have corresponding prompts.

　ButThere is no syntax error, only a black screen

　Step2：Change header('Content -Type:image/jpeg')Comment and then you can find the error message again

Just solve!

3. The reason why the picturecannot be displayed:ExtraOutput

　BOM：utf-8signatureof the encoded file, three bytes of hidden characters.is also output by! You need to encode the file into utf-8 without BOM

4. If it doesn’t work at this time, then add an ob_clean();to the header.

　The role of ob_clean()

That’s it now

Finally found the problem, I hope it can help everyone

Recommended study: "PHP Video Tutorial"

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