lib/dijit/_base/wai.js

   1 /*
   2         Copyright (c) 2004-2011, The Dojo Foundation All Rights Reserved.
   3         Available via Academic Free License >= 2.1 OR the modified BSD license.
   4         see: http://dojotoolkit.org/license for details
   5 */
   6
   7
   8 if(!dojo._hasResource["dijit._base.wai"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
   9 dojo._hasResource["dijit._base.wai"] = true;
  10 dojo.provide("dijit._base.wai");
  11
  12
  13 dijit.wai = {
  14         onload: function(){
  15                 // summary:
  16                 //              Detects if we are in high-contrast mode or not
  17
  18                 // This must be a named function and not an anonymous
  19                 // function, so that the widget parsing code can make sure it
  20                 // registers its onload function after this function.
  21                 // DO NOT USE "this" within this function.
  22
  23                 // create div for testing if high contrast mode is on or images are turned off
  24                 var div = dojo.create("div",{
  25                         id: "a11yTestNode",
  26                         style:{
  27                                 cssText:'border: 1px solid;'
  28                                         + 'border-color:red green;'
  29                                         + 'position: absolute;'
  30                                         + 'height: 5px;'
  31                                         + 'top: -999px;'
  32                                         + 'background-image: url("' + (dojo.config.blankGif || dojo.moduleUrl("dojo", "resources/blank.gif")) + '");'
  33                         }
  34                 }, dojo.body());
  35
  36                 // test it
  37                 var cs = dojo.getComputedStyle(div);
  38                 if(cs){
  39                         var bkImg = cs.backgroundImage;
  40                         var needsA11y = (cs.borderTopColor == cs.borderRightColor) || (bkImg != null && (bkImg == "none" || bkImg == "url(invalid-url:)" ));
  41                         dojo[needsA11y ? "addClass" : "removeClass"](dojo.body(), "dijit_a11y");
  42                         if(dojo.isIE){
  43                                 div.outerHTML = "";             // prevent mixed-content warning, see http://support.microsoft.com/kb/925014
  44                         }else{
  45                                 dojo.body().removeChild(div);
  46                         }
  47                 }
  48         }
  49 };
  50
  51 // Test if computer is in high contrast mode.
  52 // Make sure the a11y test runs first, before widgets are instantiated.
  53 if(dojo.isIE || dojo.isMoz){    // NOTE: checking in Safari messes things up
  54         dojo._loaders.unshift(dijit.wai.onload);
  55 }
  56
  57 dojo.mixin(dijit, {
  58         hasWaiRole: function(/*Element*/ elem, /*String?*/ role){
  59                 // summary:
  60                 //              Determines if an element has a particular role.
  61                 // returns:
  62                 //              True if elem has the specific role attribute and false if not.
  63                 //              For backwards compatibility if role parameter not provided,
  64                 //              returns true if has a role
  65                 var waiRole = this.getWaiRole(elem);
  66                 return role ? (waiRole.indexOf(role) > -1) : (waiRole.length > 0);
  67         },
  68
  69         getWaiRole: function(/*Element*/ elem){
  70                 // summary:
  71                 //              Gets the role for an element (which should be a wai role).
  72                 // returns:
  73                 //              The role of elem or an empty string if elem
  74                 //              does not have a role.
  75                  return dojo.trim((dojo.attr(elem, "role") || "").replace("wairole:",""));
  76         },
  77
  78         setWaiRole: function(/*Element*/ elem, /*String*/ role){
  79                 // summary:
  80                 //              Sets the role on an element.
  81                 // description:
  82                 //              Replace existing role attribute with new role.
  83
  84                         dojo.attr(elem, "role", role);
  85         },
  86
  87         removeWaiRole: function(/*Element*/ elem, /*String*/ role){
  88                 // summary:
  89                 //              Removes the specified role from an element.
  90                 //              Removes role attribute if no specific role provided (for backwards compat.)
  91
  92                 var roleValue = dojo.attr(elem, "role");
  93                 if(!roleValue){ return; }
  94                 if(role){
  95                         var t = dojo.trim((" " + roleValue + " ").replace(" " + role + " ", " "));
  96                         dojo.attr(elem, "role", t);
  97                 }else{
  98                         elem.removeAttribute("role");
  99                 }
 100         },
 101
 102         hasWaiState: function(/*Element*/ elem, /*String*/ state){
 103                 // summary:
 104                 //              Determines if an element has a given state.
 105                 // description:
 106                 //              Checks for an attribute called "aria-"+state.
 107                 // returns:
 108                 //              true if elem has a value for the given state and
 109                 //              false if it does not.
 110
 111                 return elem.hasAttribute ? elem.hasAttribute("aria-"+state) : !!elem.getAttribute("aria-"+state);
 112         },
 113
 114         getWaiState: function(/*Element*/ elem, /*String*/ state){
 115                 // summary:
 116                 //              Gets the value of a state on an element.
 117                 // description:
 118                 //              Checks for an attribute called "aria-"+state.
 119                 // returns:
 120                 //              The value of the requested state on elem
 121                 //              or an empty string if elem has no value for state.
 122
 123                 return elem.getAttribute("aria-"+state) || "";
 124         },
 125
 126         setWaiState: function(/*Element*/ elem, /*String*/ state, /*String*/ value){
 127                 // summary:
 128                 //              Sets a state on an element.
 129                 // description:
 130                 //              Sets an attribute called "aria-"+state.
 131
 132                 elem.setAttribute("aria-"+state, value);
 133         },
 134
 135         removeWaiState: function(/*Element*/ elem, /*String*/ state){
 136                 // summary:
 137                 //              Removes a state from an element.
 138                 // description:
 139                 //              Sets an attribute called "aria-"+state.
 140
 141                 elem.removeAttribute("aria-"+state);
 142         }
 143 });
 144
 145 }