The JavaScript function presented in this page can be used to create Multi-Level Menu. The function has three parameters:
      - parentId - the ID of the parent /category with sub-categories.
      - ctgLists - an object with parents and their direct child-lists (array with their IDs).
      - ctgData - an object with data (name, link-URL) of each list /anchor in menu.

Code of the multilevelMenu() function

// recursive function to create multilevel menu list, parentId 0 is the Root
// function addapted from: http://crisp.tweakblogs.net/blog/317/formatting-a-multi-level-menu-using-only-one-query.html
function multilevelMenu(parentId, ctgLists, ctgData) {
  var html = '';       // stores and returns the html code with Menu lists

  // if parent item with child IDs in ctgLists
  if(ctgLists[parentId]) {
    html = '<ul>';      // open UL

    // traverses the array with child IDs of current parent, and adds them in LI tags, with their data from ctgData
    for (childId in ctgLists[parentId]) {
      // define CSS class in anchors, useful to be used in CSS style to design the menu
      if(parentId == 0) var clsa = ' class="firsrli"';       // to add class to anchors in main /first categories
      else if(ctgLists[ctgLists[parentId][childId]]) var clsa = ' class="litems"';       // to add class to anchors in lists with childs
      else var clsa = '';

      // open LI
      html += '<li><a href="'+ ctgData[ctgLists[parentId][childId]].lurl +'" title="'+ ctgData[ctgLists[parentId][childId]].lname +'"'+ clsa +'>'+ ctgData[ctgLists[parentId][childId]].lname +'</a>';

      html += multilevelMenu(ctgLists[parentId][childId], ctgLists, ctgData);     // re-calls the function to find parent with child-items recursively

      html += '</li>';      // close LI
    }
    html += '</ul>';       // close UL
  }

  return html;
}

- Example of usage multilevelMenu() function:
<div id="m_menu">Here it is included the Menu, with JavaScript</div>

<script type="text/javascript"><!--
// recursive function to create multilevel menu list, $parentId 0 is the root
// function addapted from: http://crisp.tweakblogs.net/blog/317/formatting-a-multi-level-menu-using-only-one-query.html
function multilevelMenu(parentId, ctgLists, ctgData) {
  var html = '';       // stores and returns the html code with Menu lists

  // if parent item with child IDs in ctgLists
  if(ctgLists[parentId]) {
    html = '<ul>';      // open UL

    // traverses the array with child IDs of current parent, and adds them in LI tags, with their data from ctgData
    for (childId in ctgLists[parentId]) {
      // define CSS class in anchors, useful to be used in CSS style to design the menu
      if(parentId == 0) var clsa = ' class="firsrli"';       // to add class to anchors in main /first categories
      else if(ctgLists[ctgLists[parentId][childId]]) var clsa = ' class="litems"';       // to add class to anchors in lists with childs
      else var clsa = '';

      // open LI
      html += '<li><a href="'+ ctgData[ctgLists[parentId][childId]].lurl +'" title="'+ ctgData[ctgLists[parentId][childId]].lname +'"'+ clsa +'>'+ ctgData[ctgLists[parentId][childId]].lname +'</a>';

      html += multilevelMenu(ctgLists[parentId][childId], ctgLists, ctgData);     // re-calls the function to find parent with child-items recursively

      html += '</li>';      // close LI
    }
    html += '</ul>';       // close UL
  }

  return html;
}

// object with parents and their childs
var ctgLists = {
  0: [1, 33],
  1: [2, 15, 28, 31, 32],
  2: [3, 7, 12],
  3: [4, 5, 6],
  7: [8, 10, 11],
  8: [9],
  12: [13, 14],
  15: [16, 21, 22, 23, 27],
  16: [17, 18, 19, 20],
  23: [24, 25, 26],
  28: [29, 30],
  33: [34],
  34: [35, 38, 46],
  35: [36, 37],
  38: [39, 43],
  39: [40, 41, 42],
  43: [44, 45]
};

// object with link data
var ctgData = {
  0: {
    'lname': 'Root',
    'lurl': '#',
  },
  1: {
    'lname': 'CoursesWeb.net',
    'lurl': 'http://coursesweb.net/',
  },
  2: {
    'lname': 'JavaScript Courses',
    'lurl': 'http://coursesweb.net/javascript/',
  },
  3: {
    'lname': 'Tutorials',
    'lurl': 'http://coursesweb.net/javascript/tutorials_t',
  },
  4: {
    'lname': 'setTimeout - setInterva',
    'lurl': 'http://coursesweb.net/javascript/settimeout-setinterval_t',
  },
  5: {
    'lname': 'Dynamic variables',
    'lurl': 'http://coursesweb.net/javascript/dynamic-variables-javascript_t',
  },
  6: {
    'lname': 'Validate radio - checkbox',
    'lurl': 'http://coursesweb.net/javascript/validate-radio-checkbox-buttons_t',
  },
  7: {
    'lname': 'jQuery Course',
    'lurl': 'http://coursesweb.net/jquery/jquery-course',
  },
  8: {
    'lname': 'jQuery Basics',
    'lurl': 'http://coursesweb.net/jquery/jquery-basics',
  },
  9: {
    'lname': 'Selecting HTML elements',
    'lurl': 'http://coursesweb.net/jquery/jquery-basics#selelm',
  },
  10: {
    'lname': 'jQuery ajax(}',
    'lurl': 'http://coursesweb.net/jquery/jquery-ajax',
  },
  11: {
    'lname': 'slideDown - SlideUp',
    'lurl': 'http://coursesweb.net/jquery/slidedown-slideup',
  },
  12: {
    'lname': 'JS Scripts',
    'lurl': 'http://coursesweb.net/javascript/javascript-scripts_s2',
  },
  13: {
    'lname': 'JS Trivia Game',
    'lurl': 'http://coursesweb.net/javascript/trivia-game-script_s2',
  },
  14: {
    'lname': 'Scroll to Top Page Button',
    'lurl': 'http://coursesweb.net/javascript/trivia-game-script_s2',
  },
  15: {
    'lname': 'PHP-MySQL Course',
    'lurl': 'http://coursesweb.net/php-mysql/',
  },
  16: {
    'lname': 'Lessons',
    'lurl': 'http://coursesweb.net/php-mysql/lessons',
  },
  17: {
    'lname': 'PHP Strings',
    'lurl': 'http://coursesweb.net/php-mysql/strings',
  },
  18: {
    'lname': 'Constants',
    'lurl': 'http://coursesweb.net/php-mysql/constants',
  },
  19: {
    'lname': 'Arrays',
    'lurl': 'http://coursesweb.net/php-mysql/arrays',
  },
  20: {
    'lname': 'PHP PDO',
    'lurl': 'http://coursesweb.net/php-mysql/pdo-introduction-connection-database',
  },
  21: {
    'lname': 'Tutorials',
    'lurl': 'http://coursesweb.net/php-mysql/tutorials_t',
  },
  22: {
    'lname': 'Uploading multiple files',
    'lurl': 'http://coursesweb.net/php-mysql/uploading-multiple-files_t',
  },
  23: {
    'lname': 'Common PHP Errors',
    'lurl': 'http://coursesweb.net/php-mysql/common-php-errors-solution_t',
  },
  24: {
    'lname': 'Unespected /',
    'lurl': 'http://coursesweb.net/php-mysql/common-php-errors-solution_t#perr1_0',
  },
  25: {
    'lname': 'headers already sent',
    'lurl': 'http://coursesweb.net/php-mysql/common-php-errors-solution_t#perr12_11',
  },
  26: {
    'lname': 'Undefined variable',
    'lurl': 'http://coursesweb.net/php-mysql/common-php-errors-solution_t#perr13_12',
  },
  27: {
    'lname': 'Code Snippets',
    'lurl': 'http://coursesweb.net/php-mysql/common-php-errors-solution_t#perr13_12',
  },
  28: {
    'lname': 'Ajax Lessons',
    'lurl': 'http://coursesweb.net/ajax/',
  },
  29: {
    'lname': 'Tutorials',
    'lurl': 'http://coursesweb.net/ajax/tutorials_t',
  },
  30: {
    'lname': 'Download Resources',
    'lurl': 'http://coursesweb.net/ajax/download_l2',
  },
  31: {
    'lname': 'HTML Course',
    'lurl': 'http://coursesweb.net/html/',
  },
  32: {
    'lname': 'CSS Course',
    'lurl': 'http://coursesweb.net/css/',
  },
  33: {
    'lname': 'MarPlo.net',
    'lurl': 'http://marplo.net/',
  },
  34: {
    'lname': 'JavaScript',
    'lurl': 'http://marplo.net/javascript/',
  },
  35: {
    'lname': 'JS Lessons',
    'lurl': 'http://marplo.net/javascript/lectii-js',
  },
  36: {
    'lname': 'Syntax',
    'lurl': 'http://marplo.net/javascript/sintaxajs.html',
  },
  37: {
    'lname': 'Functions',
    'lurl': 'http://marplo.net/javascript/functii1.html',
  },
  38: {
    'lname': 'jQuery',
    'lurl': 'http://marplo.net/javascript/curs-jquery-tutoriale-js',
  },
  39: {
    'lname': 'jQuery CSS',
    'lurl': 'http://marplo.net/javascript/jquery-css-js',
  },
  40: {
    'lname': 'CSS Properties',
    'lurl': 'http://marplo.net/javascript/jquery-css-js#setcss',
  },
  41: {
    'lname': 'Add / Delete Classes',
    'lurl': 'http://marplo.net/javascript/jquery-css-js#arclass',
  },
  42: {
    'lname': 'Check Classes',
    'lurl': 'http://marplo.net/javascript/jquery-css-js#ceclass',
  },
  43: {
    'lname': 'fadeIn - fadeOut',
    'lurl': 'http://marplo.net/javascript/jquery-fadein-fadeout-js',
  },
  44: {
    'lname': 'fadeIn - fadeOut',
    'lurl': 'http://marplo.net/javascript/jquery-fadein-fadeout-js',
  },
  45: {
    'lname': 'fadeTo',
    'lurl': 'http://marplo.net/javascript/jquery-fadein-fadeout-js#fadeto',
  },
  46: {
    'lname': 'JS Tutorials',
    'lurl': 'http://marplo.net/javascript/tutoriale-js',
  }
};

// adds the html menu lists in the DIV with id="m_menu"
document.getElementById('m_menu').innerHTML = multilevelMenu(0, ctgLists, ctgData);
//-->
</script>
The code above will build and display these HTML lists:

- To display properly these memu lists, apply CSS properties to design the dropdown menu.
Here's two CSS codes that can be used for Horizontal and Vertical Dropdown Menu. The menu-lists are included into a DIV with id="m_menu" (click on the image to see how the menu looks):

CSS code for Horizontal-Vertical Menu

Horizontal-Vertical menu

CSS code for Vertical-Horizontal Menu

Vertical-Horizontal menu

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Which tag is used to add definition lists into a <dl> element?
<dt> <dd> <li>
<dl>
 <dt>HTML</dt>
  <dd> - Hyper Text Markup Language</dd>
  <dd> - Language for web pages</dd>
</dl>
Which CSS property can hide an element on page, letting an empty space in its place?
display position visibility
#id {
  visibility: hidden;
}
Click on the event which is triggered when the mouse clicks on an object.
onclick onmouseover onfocus
document.getElementById("id").onclick = function(){
  alert("http://CoursesWeb.net/");
}
Indicate the PHP variable that contains the contents of both $_GET, $_POST, and $_COOKIE arrays.
$_SESSION $_GET $_REQUEST
if(isset($_REQUEST["id"])) {
  echo $_REQUEST["id"];
}
Recursive function to create Multi-Level Menu in JavaScript

Last accessed pages

  1. Register and show online users and visitors (21149)
  2. Cake Shop (657)
  3. SHA512 Encrypt hash in JavaScript (9327)
  4. My New Room 2 (353)
  5. Ajax-PHP Rating Stars Script (12781)

Popular pages this month

  1. Flash Games - Free online Games (1360)
  2. Qwop (1158)
  3. Tunnel Rush (1062)
  4. Courses Web: PHP-MySQL JavaScript Ajax HTML CSS Flash-AS3 (983)
  5. Drag Racer V3 (758)