RegEx for Javascript to allow only alphanumeric

Question

I need to find a reg ex that only allows alphanumeric. So far, everyone I try only works if the string is alphanumeric, meaning contains both a letter and a number. I just w

Answer 1

This will work

^(?=.*[a-zA-Z])(?=.*[0-9])[a-zA-Z0-9]+$

It accept only alphanumeriuc characters alone:
test cases pased :

dGgs1s23 - valid
12fUgdf  - valid,
121232   - invalid, 
abchfe   - invalid,
 abd()*  - invalid, 
42232^5$ - invalid

or

You can also try this one. this expression satisfied at least one number and one character and no other special characters

^(?=.*[0-9])(?=.*[a-zA-Z])([a-zA-Z0-9]+)$

in angular can test like:

$scope.str = '12fUgdf';
var pattern = new RegExp('^(?=.*[0-9])(?=.*[a-zA-Z])([a-zA-Z0-9]+)$');
$scope.testResult = pattern.test($scope.str);

PLUNKER DEMO

Refered:Regular expression for alphanumeric in Angularjs