Create a Drop-Down list using JavaScript and CSS/zh


 * 参见： 

Requirements
Ability to change your MediaWiki:Common.js and MediaWiki:Monobook.css

Common.js代码
/* Any JavaScript here will be loaded for all users on every page load. */

function ddm {

// Variables, change these in case you need to set other class names (mmhide_ for    // contribute users for example) var parentClass = 'isParent'; //gets applied when the LI has a nested UL   var activeParentClass = 'isActive'; //gets applied when the nested UL is visible var preventHoverClass = 'nohover'; //denotes a navigation that should not get any hover effects var indicateJSClass = 'dhtml'; //gets applied to the main navigation when Javascript is available var toHideClass = 'hiddenChild'; //gets applied to hide the nested UL   var toShowClass = 'shownChild'; //gets applied to show the nested UL    var currentClass = 'current'; //denotes the current active sub element and prevents collapsing var d = document.getElementById('nav'); //denotes the navigation element

// if DOM is not available stop right here. if (!document.getElementById && !document.createTextNode) { return; }

// if the navigation element is available, apply the class denoting DHTML capabilities if (d) { d.className += d.className == '' ? indicateJSClass : ' ' + indicateJSClass; var lis, i, firstUL, j, apply;

// loop through all LIs and check which ones have a nested UL       lis = d.getElementsByTagName('li'); for (i = 0; i < lis.length; i++) { firstUL = lis[i].getElementsByTagName('ul')[0]; // if there is a nested UL, deactivate the first nested link and apply the class to show // there is a nested list if (firstUL) { lis[i].childNodes[0].onclick = function { return false; };               lis[i].className += lis[i].className == '' ? parentClass : ' ' + parentClass; // check if there is a "current" element apply = true; if (new RegExp('\\b' + currentClass + '\\b').test(lis[i].className)) { apply = false; }               if (apply) { for (j = 0; j < firstUL.getElementsByTagName('li').length; j++) { if (new RegExp('\\b' + currentClass + '\\b').test(firstUL.getElementsByTagName('li')[j].className)) { apply = false; break; }                   }                }                // if there is no current element, apply the class to hide the nested list if (apply) { firstUL.className += firstUL.className == '' ? toHideClass : ' ' + toHideClass; // check if there is a class to prevent hover effects and only apply the function // onclick if that is the case, otherwise apply it onclick and onhover if (new RegExp('\\b' + preventHoverClass + '\\b').test(d.className)) { lis[i].onclick = function { doddm(this); };                   } else { lis[i].onclick = function { doddm(this); };                       lis[i].onmouseover = function { doddm(this); };                       lis[i].onmouseout = function { doddm(null); };                   }                    // if there is a current element, define the list as being kept open and apply the // classes to show the nested list and define the parent LI as an active one } else { lis[i].keepopen = 1; firstUL.className += firstUL.className == '' ? toShowClass : ' ' + toShowClass; lis[i].className = lis[i].className.replace(parentClass, activeParentClass); }           }        }    }    // function to show and hide the nested lists and add the classes to the parent LIs function doddm(o) { var childUL, isobj, swap;

// loop through all LIs of the navigation lis = d.getElementsByTagName('li'); for (i = 0; i < lis.length; i++) { isobj = lis[i] == o;           // function to exchange class names in an object swap = function(tmpobj, tmporg, tmprep) { tmpobj.className = tmpobj.className.replace(tmporg, tmprep); };           // if the current LI does not have an indicator to be kept visible if (!lis[i].keepopen) { childUL = lis[i].getElementsByTagName('ul')[0]; // check if there is a nested UL and if the current LI is not the one clicked on               // and exchange the classes accordingly (ie. hide all other nested lists and                 // make the LIs parent rather than active.                if (childUL) {                    if (new RegExp('\\b' + preventHoverClass + '\\b').test(d.className)) {                        if (new RegExp('\\b' + activeParentClass + '\\b').test(lis[i].className)) {                            swap(childUL, isobj ? toShowClass : toHideClass, isobj ? toHideClass : toShowClass);                           swap(lis[i], isobj ? activeParentClass : parentClass, isobj ? parentClass : activeParentClass);                       } else {

swap(childUL, isobj ? toHideClass : toShowClass, isobj ? toShowClass : toHideClass); swap(lis[i], isobj ? parentClass : activeParentClass, isobj ? activeParentClass : parentClass); }                   } else { swap(childUL, isobj ? toHideClass : toShowClass, isobj ? toShowClass : toHideClass); swap(lis[i], isobj ? parentClass : activeParentClass, isobj ? activeParentClass : parentClass); }               }            }        }    } } window.onload = function { ddm; // add other functions to be called onload below };

Monobook.css
/*Main Line Not Just Link Margin - From left Side*/ ul#nav{ margin:3; padding:2; list-style-type:none; border:none; background:#fff; padding:.5em; width:auto; } /*Drop Menu Line Colors that "flash" to load Menu*/ ul#nav li ul{ background:#fff; margin:0; padding:5; width:auto; } ul#nav li{ position:relative; margin:5; width:auto; padding:5; list-style-type:none; background:333; color:#333; line-height:150%; } /*Main Link Font Color and "loading border" set to fff for invisibility*/ ul#nav a{ border:1px solid #fff; color:#333; text-decoration:none; display:block; } /*Mouse over option text color*/ ul#nav a:hover{ border:1px inset #333; background:#333; color:#333; } /*Color of Text option drop down without mouse on them.*/ ul#nav li li a{ padding-left:1em; color:#006AFF; text-decoration:none; display:block; } ul#nav li li a:hover{ background:#cef; }

/* DDM relative dropdown example */ .hiddenChild{ position: absolute; left: -999em; } .shownChild{ left:-1px; } p{ clear:both;float:none; } /*Parent initial border information white fff set to hide "optional options area"*/ ul#nav.dhtml{ list-style-image: none; display: block; position:relative; width:auto; border:2px solid #fff; background:#333 margin:2; padding:2; list-style-type:none; height:1.5em; } /*WIDTH IS TOP OPTION WIDTH. (OPTION WIDTH - 1)*/ ul#nav.dhtml li{ position:relative; float:left; width:9em; border-right:1px solid #333; border-top:1px solid #333; border-left:1px solid #333; border-bottom:1px solid #333; } /*Initial background color of options with mouse hovered over main link*/ ul#nav.dhtml ul{ list-style-image: none; display: block; top:1.5em; position:absolute; border-top:1px solid #333; border-right:1px solid #333; border-left:1px solid #333; background:#333; width:auto; z-index:10; } ul#nav.dhtml li a,ul#nav.dhtml li a:hover{ border:none; background:#333; } ul#nav.dhtml li a{ padding:0 .5em; background:#333; } /*Options background color when main category is highlighted with mouse and options not selected WIDTH IS OPTIONS WIDTH*/ ul#nav.dhtml ul li{ border:none; width:9em; background:#fff; } /*No Mouse On Main Link Background*/ ul#nav.dhtml li.isParent{ background:#cef; } /*Yes Mouse On Main Link Background*/ ul#nav.dhtml li.isActive{ background:#fff; } ul#nav.dhtml li.isActive a{ background:cef; } ul#nav.dhtml li.isActive ul a{ padding:0 .5em; } ul#nav.dhtml a:hover{ background:#333; } ul#nav.dhtml li.isParent a:hover{ background:#333; } ul#nav.dhtml li.isActive ul a:hover{ background:#333; }

Code / Menu / Listing Used in Wiki Example
 NameofLink  Option1  Option2  Option3  Option4  Option5 

Thus creating a fully functional drop down list in your specified location.

示例代码：

 Shortcuts  Carnivores </li> Herbivores </li> Reptiles </li> Amphibians </li> Mammals </li></ul></li></ul></ul> Image of Sample Above on WikiMedia Forums: http://www.mwusers.com/forums/attachment.php?attachmentid=131&d=1234407968

参见

 * OOjs_UI/Widgets/Selects_and_Options
 * OOjs_UI/Widgets/Selects_and_Options