How to reset first position before using animate left

How to reset first position before using animate left

Hi, i'm really new for jquery, i search over the internet about jquery, and start to learn.
My problem maybe seems silly, I want to make 3 panel that functionally like we browse files in mac. I already suceed made 2 panel, the problem is, at the first load, the second panel already shown. I want it keep hide, until people clicked the button. 

This what i have, (please click the home text)

This the complete script
  1. <html>
  2. <head>
  3. <style type="text/css" media="screen">
  4. html, body, div, span, applet, object, iframe,h1, h2, h3, h4, h5, h6, p, blockquote, pre,a, abbr, acronym, address, big, cite, code,del, dfn, em, img, ins, kbd, q, s, samp,small, strike, strong, sub, sup, tt, var,b, u, i, center,dl, dt, dd, ol, ul, li,fieldset, form, label, legend,table, caption, tbody, tfoot, thead, tr, th, td,article, aside, canvas, details, embed, figure, figcaption, footer, header, hgroup, menu, nav, output, ruby, section, summary,time, mark, audio, video {
  5. margin: 0;
  6. padding: 0;
  7. border: 0;
  8. font-size: 100%;
  9. font: inherit;
  10. vertical-align: baseline;
  11. }
  12. .container {
  13. width: 100%;
  14. }
  15. .menu_panel {
  16. width: 15%;
  17. float: left;
  18. background-color: #aaa;
  19. height: 1000px;
  20. }
  21. .content_panel {
  22. width: 50%;
  23. float:left;
  24. background-color: #DEA140;
  25. height: 1000px;
  26. position: relative;
  27. left:0;
  28. z-index: -1;
  29. }
  30. .hidden {
  31. display: none;
  32. }
  33. </style>
  34. <script src="jquery-1.5.min.js" type="text/javascript"></script>
  35. </head>
  36. <body>
  37. <div class="container">
  38. <div class="menu_panel">
  39. <ul>
  40. <li class="menu_head">Home</li>
  41. <ul class="menu_body">
  42. <li>Feature Slider</li>
  43. <li>Audio</li>
  44. <li>Feature Album</li>
  45. <li>Social Network Link</li>
  46. </ul>
  47. <li class="menu_head">Home</li>
  48. <ul class="menu_body">
  49. <li>Feature Slider</li>
  50. <li>Audio</li>
  51. <li>Feature Album</li>
  52. <li>Social Network Link</li>
  53. </ul>
  54. </ul>
  55. </div>
  56. <div class="content_panel" id="slide">
  57. <iframe src="content_panel.htm" width="100%" height="100%">
  58. </iframe>
  59. </div>
  60. </div>
  61. <script type="text/javascript">
  62. $(document).ready(function() {
  63. $(".menu_body").hide();
  64. $(".menu_head").click(function() {
  65. $(this).next(".menu_body").slideToggle(600);
  66. });
  67. $('.menu_body li').click(function() {
  68. var $lefty = $('#slide');    
  69. $lefty.animate({
  70. left: parseInt($lefty.css('left'),10) == 0 ?
  71. -$lefty.outerWidth() :
  72. 0
  73. });
  74. });    
  75. });
  76. </script>
  77. </body>
  78. </html>

Can anybody help me?