Telephone field (HTML5)

HTML

<form>
  <input id="telInput" 
         type="tel" 
         required="true" 
         pattern="\+[0-9]{3}\-[0-9]{3}\-[0-9]{2}\-[0-9]{2}\-[0-9]{2}"
         placeholder="+359-888-88-88-88"
         oninvalid="this.setCustomValidity('Dude!')"
         oninput="this.setCustomValidity('')" />
    <br/>
    <input type="submit" value="Apply" />
    <input type="reset" value="reset" />
  </form>