Javascript test string for only letters and numbers [duplicate]

Question

I have the following functions

JavaScript

function lettersNumbersOnly(string){
   if (/[A-Za-z0-9]/.test(string)) {
     console.log('Clean');
   }else{
     console.log('Not Matching');
   }
}

$(".test-input").change(function(){
  lettersNumbersOnly($(this).val());
});

If I were to put letters and numbers into that .test-input field, I get the "Clean". BUT if I put characters like !2@$% etc. I still get the "Clean" which is not what I want. I just want strictly letters and numbers. Any suggestions?

Answer 1

Use start and end anchors for complete string match and + for one or more repetition of character class.

if (/^[A-Za-z0-9]+$/.test(string))