How to use JavaScript regular expressions to verify that an input contains more than zero characters

Can someone help me with a simple regex issue? I've tried searching online but couldn't find a suitable example. I'm struggling with regex and just need to ensure that an input contains more than 1 character (i.e. is not blank). My code uses Angular's ng-pattern directive.

<input type="text" ng-model="username" ng-pattern="/regex/">

I want to make sure there is something in the input (not empty). I've tried a few examples, but the problem is that even after clearing the input, Angular still recognizes it as valid. I need it to fail if the input becomes empty again, but not on initial load. Any assistance would be greatly appreciated.

EDIT: Basically, I need a regex that will check if the field is not blank. You can view my plnkr example here.

javascriptregexangularjs

Answer №1

To ensure that a field is required, simply add the required attribute to the input element:

<input type="text" ng-model="username" name="username" required>

Take a look at this pluckr fork for an example: http://plnkr.co/edit/VwY1WPdCocKHwww69ZSj?p=preview

For more information, refer to the documentation here: http://docs.angularjs.org/api/ng.directive:input#usage_parameters

If you insist on using ng-pattern, make sure to include start and end of input markers (^ and $):

<input type="text" ng-model="username" ng-pattern="/^$/">

Keep in mind that this will only validate a blank input (where the value matches the pattern).

Answer №2

Remember to utilize the pattern /.+/. In this context, . represents any character excluding new line characters, while + indicates at least one occurrence.

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