how to check if the value of a field is null or not

Summary

how to check if the value of a field is null or not

Content

Hey,

 

I've a text field at the form, if the value of the field is not null, I wish to perform certain action. So for checking, if the value of the field is null, I'm using

 

if($SearchEmployeeEntityDetailArchetypeRecord.getValue('state')!='undefined'){

     alert("Value entered");

}

But this doesn't seem to work fine, It alerts "Value entered" even when no value is entered for text field.

 

Any help will be really appreciated.

 

 

Thanks!