Why you have to enter a verification code for registration and what it means, it s always unclear.

Mainly to prevent OCR.

What the captcha does:

1）.Captcha is generally to prevent batch registration, and it looks difficult to the human eye, let alone a machine. Two like the post bar is not logged in to post to enter the verification code is probably to prevent the occurrence of large-scale anonymous replies At present, many ** in order to prevent users from using robots to automatically register, log in, and irrigate, all use verification code technology.

The so-called verification code is to generate a string of randomly generated numbers or symbols, add some interfering pixels (to prevent OCR), and the user will recognize the verification code information by the naked eye, enter the form to submit** verification, and only after the verification is successful can a certain function be used.

Common captchas.

1. Four-digit number, a random one-digit string, the most original verification code, the verification effect is almost zero.

2. CSDN** user login is in GIF format, which is currently commonly used as a random number ** verification code. **The characters on the ** are more decent, and the verification effect is better than the previous one. For those who do not have basic graphic iconography knowledge, it is unbreakable!

It's a pity that the program that reads it, on the first day that csdn used it, seems to have been published in the forum, which is really pitiful!

3,QQ**User login is in png format,**Random numbers + random capital English letters,The whole composition is a bit flamboyant,Every time you refresh it,Each character will change its position! Sometimes the ** that comes out can't be recognized by the human eye, it's amazing....

4. When MS hotmail is applied, it is in bmp format, random number + random capital English letter + random interference pixel + random position.

5, Google's gmail registration is in jpg format, random English letters + random color + random position + random length. 6. Other major forums are in XBM format, and the content is random.

Significance: In order to prevent users from using robots to automatically register, log in, and irrigate, many ** have adopted captcha technology. The so-called verification code is to generate a string of randomly generated numbers or symbols, add some interfering pixels (to prevent OCR), and the user will recognize the verification code information by the naked eye, enter the form to submit** verification, and only after the verification is successful can a certain function be used.

Summary. Answer: It is possible that there is no error in the verification code you entered, but there is still an error, which may be one of the following two situations:

1. Refresh problem on the page The verification code of each refresh page login will be changed, if the verification code is wrong, the system will replace the verification code, which is a possible page or the previous verification code, that is.

Why is the verification code filled in correctly, but it always can't be registered, and it shows that the verification is not written correctly.

Answer: It is possible that there is no error in the orange test code that you enter the volcano, but there is still a prompt error, which may be one of the following two situations: 1. Refresh the problem on the page The verification code of each refresh page login will be changed, if the verification code is wrong, the system will replace the verification code, which is a possible page or the previous verification code, that is.

Fellow, I really didn't understand, I can be more specific.

Answer: It is possible that there is no error in the verification code you entered, if there is an error, it may be one of the following three situations: 1. Refresh the problem on the page Every time you refresh the page, the verification code will be changed in the middle of the phone, and if the verification code is wrong, the system will replace the verification code, and then the page may still be the original verification code, so you may enter.

When registering an ** account and submitting the registration information, the system prompts the verification code "entered incorrectly, please re-enter" for the following reasons:

1. The verification code entered does not match the ** display.

Second, the input method used is incorrect.

Solution: The entered verification code is valid only when the input method is in English or half-width, otherwise the system will prompt "Input error, please re-enter".

3. Browser problems.

Step 1: Open your browser and select "Tools" in the menu - Internet Options;

Step 2: Select "Delete Files" in the "Temporary Files of the Internet" item in "General", and select "Clear History" in the "History" item;

Step 3: Close the browser, reopen the registration page and try again.

It is possible that the verification code you entered is indeed not wrong, but there is still a prompt error, which may be one of the following two situations: 1. Refresh problem on the page The verification code of each refresh page login will be changed, if the verification code is wrong, the system will replace the verification code, this is the possible page or the previous verification code, that is, you will not enter the same registration code twice, and then re-enter the new verification code after seeing the verification code change. Second, the full-width of the input method half-width problem The full-width input number of the input method is not the same, that is, the full-width number 1234 and the half-width number 1234 are different, the verification code input of Sina blog only supports half-width numbers, and the full-width number is entered as shown in the figure below), although the number is correct, it still cannot pass the verification.

Entering full-width numbers cannot be verified In addition, with the gradual increase of new users of Sina Blog, the system must be upgraded and maintained frequently. It's normal for some unexpected issues to occur, and some users will be affected. Keywords:

Verification code What should I do if I encounter a verification code problem when logging in to a blog, publishing an article, or leaving a blog message? 1. Please set the security level of your browser to medium. 2. Clean your browser history and cookies.

3. If you are in China, please set the computer time zone to the Beijing time zone, and the tick in front of the Internet time will be automatically synchronized with the Internet time server, and the time and date will be set correctly after the spike. 4. Close the browser, re-open the blog homepage to log in, and do not open other blog pages. 5. When clicking the login button, please be sure not to click continuously.

Debug the relevant options correctly in the browser Finally, it's important to note that the captcha is time-sensitive, and the page will refresh automatically even if you don't refresh it every once in a while. Therefore, if you don't log in for a period of time, the verification code will also change.