Example code of regular expression for form verification _ javascript skills

This article mainly introduces the details of the regular expression instance code for form verification. For more information, see the following figure:

First, I want to explain some symbolic meanings to you.

1./^ $/This is a common format.

^ Match the start position of the input string; $ match the end position of the input string

2. enter the functions to be implemented.

* Matches the previous subexpression zero or multiple times;
+ Match the previous subexpression once or multiple times;
? Match the previous subexpression zero or one time;
\ D matches a numeric character, which is equivalent to [0-9]

The following code analyzes the regular expression and verifies the regular expression. the specific code is as follows:

      
    Common regular expression verification forms