Active Current Page

<script>
  $(document).ready(function() {
      var url = window.location; 
      var element = $('ul.sidebar-menu a').filter(function() {
      return this.href == url || url.href.indexOf(this.href) == 0; }).parent().addClass('active');
      if (element.is('li')) { 
           element.addClass('active').parent().parent('li').addClass('active')
       }
  });
</script>

----
Melhor Opção:

$(function() {
  // this will get the full URL at the address bar
  var url = window.location.href;

  // passes on every "a" tag
  $(".menu .content-menu ul a").each(function() {
    // checks if its the same on the address bar
    if (url == this.href) {
      $(this)
        .closest("li")
        .addClass("active");
    }
  });
});