Regex Expression validation in javascript

Question

Regex to check the first character is in uppercase and allow only alphanumeric,not allow the special charcter. Thank you Advance

    function checkName(val) {    
    var alpha = document.getElementById(val).value;    
    var filter = /^[a-zA-Z0-9 ]*$/;    
    if (!filter.test(alpha)) {
        alert("Please Enter Alphanumeric Only");
        return false;                                                   
    } 
    return true;   
  }

i Used This its working properly for checking alphanumeric but for first character uppercase its not working where can i modify my regex expression or any solution.

gurvinder372 · Accepted Answer · 2016-04-05 05:36:27Z

1

try

/^[A-Z][a-zA-Z0-9]+/

For example

/^[A-Z][a-zA-Z0-9]+/.test("Asd");

answered Apr 5, 2016 at 5:36

gurvinder372

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5 Comments

shafi7468 Over a year ago

if i replace my regex expression with your regex then alert messege will popup at every time if i enter alphanumeric letters also

gurvinder372 Over a year ago

@Shafi74 it won't if you enter first character as uppercase.

shafi7468 Over a year ago

If I enter first character as lowercase it should be validate

gurvinder372 Over a year ago

@Shafi74 are you saying that if first character is lowercase then also it is valid? Then you question is not in synch with your comment.

shafi7468 Over a year ago

i will give an example if i enter first character as lowercase like aBCD then alert messege should be (First Letter Shoulb Be UpperCase) or automaticaly first character will change like ABCD. Thanq For responding please fulfill my requirement either using regex or any methods

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