title: magento 1.9, required attribute is not selected (Alert), where to find
body: <p>When I create a dropdown attribute mandatory choice, it creates the attribute in the product normally.
    When you do not choose an option, and try to add the product to cart, it generates an alert java script, as shown in image 1.
  I need to know where, in which js file, I find this code: alert ('Please, select item');</p>
  
  <p>NOTE:'ve looked in several files, but do not have much knowledge in magento to find the file.</p>
  
  <p>Thank you so much
  <img src="https://i.stack.imgur.com/jAmb2.png" alt="enter image description here"></p>