用于验证特殊字符串的Javascript正则表达式

Question

I am new to javascript regular expressions.Any-way i want to valiadate a string that matches some conditions

Here are the conditions

1.String contains only 9 characters

2.First two letters must be alphabets.

3.third letter must be '-' this.

4.Remaining 6 letters must be digits

function validateInput(str){
   if(str.length>9){
    alert("Exeeds maximum limit");
  }
}

How can i do the rest of the validations using regex?

Answer 1

The following regex matches exactly what you described:

 /^[a-z]{2}-\d{6}$/i

regex101 demo

• ^ matches the start of string (preventing matches in the middle of the string)
• [az]{2} matches 1 letter, repeated 2 times (thus it matches 2 letters).
• - matches a literal dash
• \\d{6} matches a digit, repeated 6 times (6 digits).
• $ matches the end of string.
• Mode : /i - case-insensitive match. So [az] also matches uppercase letters as well.

---

Code

 function validateInput(str){ if(/^[az]{2}-\\d{6}$/i.test(str)){ document.body.innerText += str + "\\t- Valid input\\n"; } else { document.body.innerText += str + "\\t- Invalid input\\n"; } } validateInput("xY-123456"); validateInput("abc-12345"); 

^{Note: using document.body.innerText as a way to output in the Code Snippet, but it shouldn't be used in your code}