Create PHP tree menu

-------------------DB-Structure------------------ | ID Name Parent Sort | | 1 menu1 0 3 | | 2 menu2 0 2 | | 3 menu3-1 6 1 | | 4 menu3-2 6 1 | | 5 menu3-2-1 4 1 | | 6 menu3 0 1 | --------------------------------------------------- The generated html should look like this: <ul> <li><a href="?c=3">menu3</a</li> <li><a href="?c=2">menu2</a></li> <li><a href="?c=1">menu1</a></li> </ul> When user clicks menu1 it should look like this: <ul> <li><a href="?c=3" class="active">menu3</a <ul> <li><a href="?c=3_3">menu3-1</a></li> <li><a href="?c=3_4">menu3-2</a></li> </ul> </li> <li><a href="?c=2">menu2</a></li> <li><a href="?c=3">menu3</a></li> </ul> If user then clicks menu3-2 it should look like this: <ul> <li><a href="?c=3" class="active">menu3</a <ul> <li><a href="?c=3_3">menu3-1</a></li> <li><a href="?c=3_4" class="active">menu3-2</a> <ul> <li><a href="?c=3_4_5">menu3-2-1</a></li> </ul> </li> </ul> </li> <li><a href="?c=2">menu2</a></li> <li><a href="?c=3">menu3</a></li> </ul> ------------------------------------------------------------------------- From the beginning only the menu-items with Parent-ID "0" will show up. When clicking on an menu-item the page should reload and show the sub category, based on the query string. Requirements: No CSS. No Javascript. Get menu structure from mySQL into an array. Generate the menu from the created array. Please let me know if I wasn't clear enough.