title: Query a SharePoint list with JavaScript
body: <p>I am a new SharePoint developer, and I am finding SharePoint to be a bit difficult. I have been looking for a way to query a SharePoint 2013 list with JavaScript for a while now, and I can't find an clear solutions. </p>
  
  <p>What I am trying to do is to validate if an entered email address exists in my "subscription list". This will occur every time a certain button is clicked. The validation will happen in a modal view which I am yet still trying to create.</p>
  
  <p>Some of the posts I have seen online talk about the <code>sp.js</code> file which I am not sure where I will find. Also, are the some good tutorials for SharePoint 2013.</p>