How to apply Hovering on html area tag?

Question

I am trying to hover the area tag of HTML. I tried this in CSS:

area:hover {     border:1px solid black; } 

This is the HTML on which it should be applied.

<!-- This imagemap inserted by Gwyn's Imagemap Selector http://gwynethllewelyn.net/gwyns-imagemap-selector/ --> <img src='http://dailyaeen.com.pk/epaper/wp-content/uploads/2012/09/27+Sep+2012-1.jpg?1349003469874' usemap='#imgmap_css_container_imgmap201293016112' class='imgmap_css_container' title='imgmap201293016112' alt='imgmap201293016112' id='img-imgmap201293016112' /> <map id='imgmap201293016112' name='imgmap_css_container_imgmap201293016112'>     <area shape="poly" coords="2,0,604,-3,611,-3,611,166,346,165,345,130,-2,130,-2,124,1,128,1,126" href="" alt="imgmap201293016112-0" title="imgmap201293016112-0" class="imgmap201293016112-area" id="imgmap201293016112-area-0" />     <area shape="rect" coords="1,131,341,213" href="" alt="imgmap201293016112-1" title="imgmap201293016112-1" class="imgmap201293016112-area" id="imgmap201293016112-area-1" />     <area shape="rect" coords="346,166,614,241" href="" alt="imgmap201293016112-2" title="imgmap201293016112-2" class="imgmap201293016112-area" id="imgmap201293016112-area-2" />     <area shape="poly" coords="917,242,344,239,345,496,574,495,575,435,917,433" href="" alt="imgmap201293016112-3" title="imgmap201293016112-3" class="imgmap201293016112-area" id="imgmap201293016112-area-3" />     <area shape="rect" coords="1,416,341,494" href="" alt="imgmap201293016112-4" title="imgmap201293016112-4" class="imgmap201293016112-area" id="imgmap201293016112-area-4" />     <area shape="rect" coords="1,215,341,410" href="" alt="imgmap201293016112-5" title="imgmap201293016112-5" class="imgmap201293016112-area" id="imgmap201293016112-area-5" />     <area shape="poly" coords="916,533,916,436,578,436,576,495,806,496,807,535" href="" alt="imgmap201293016112-6" title="imgmap201293016112-6" class="imgmap201293016112-area" id="imgmap201293016112-area-6" />     <area shape="rect" coords="805,536,918,614" href="" alt="imgmap201293016112-7" title="imgmap201293016112-7" class="imgmap201293016112-area" id="imgmap201293016112-area-7" />     <area shape="rect" coords="461,494,803,616" href="" alt="imgmap201293016112-8" title="imgmap201293016112-8" class="imgmap201293016112-area" id="imgmap201293016112-area-8" />     <area shape="rect" coords="0,497,223,616" href="" alt="imgmap201293016112-9" title="imgmap201293016112-9" class="imgmap201293016112-area" id="imgmap201293016112-area-9" />     <area shape="rect" coords="230,494,456,614" href="" alt="imgmap201293016112-10" title="imgmap201293016112-10" class="imgmap201293016112-area" id="imgmap201293016112-area-10" />     <area shape="rect" coords="345,935,572,1082" href="" alt="imgmap201293016112-11" title="imgmap201293016112-11" class="imgmap201293016112-area" id="imgmap201293016112-area-11" />     <area shape="rect" coords="1,617,457,760" href="" alt="imgmap201293016112-12" title="imgmap201293016112-12" class="imgmap201293016112-area" id="imgmap201293016112-area-12" />     <area shape="rect" coords="345,760,577,847" href="" alt="imgmap201293016112-13" title="imgmap201293016112-13" class="imgmap201293016112-area" id="imgmap201293016112-area-13" />     <area shape="rect" coords="0,759,344,906" href="" alt="imgmap201293016112-14" title="imgmap201293016112-14" class="imgmap201293016112-area" id="imgmap201293016112-area-14" />     <area shape="rect" coords="346,850,571,935" href="" alt="imgmap201293016112-15" title="imgmap201293016112-15" class="imgmap201293016112-area" id="imgmap201293016112-area-15" />     <area shape="rect" coords="578,761,915,865" href="" alt="imgmap201293016112-16" title="imgmap201293016112-16" class="imgmap201293016112-area" id="imgmap201293016112-area-16" />     <area shape="rect" coords="0,1017,226,1085" href="" alt="imgmap201293016112-17" title="imgmap201293016112-17" class="imgmap201293016112-area" id="imgmap201293016112-area-17" />     <area shape="rect" coords="0,908,342,1017" href="" alt="imgmap201293016112-18" title="imgmap201293016112-18" class="imgmap201293016112-area" id="imgmap201293016112-area-18" />     <area shape="rect" coords="229,1010,342,1084" href="" alt="imgmap201293016112-19" title="imgmap201293016112-19" class="imgmap201293016112-area" id="imgmap201293016112-area-19" />     <area shape="rect" coords="0,1086,340,1206" href="" alt="imgmap201293016112-20" title="imgmap201293016112-20" class="imgmap201293016112-area" id="imgmap201293016112-area-20" />     <area shape="rect" coords="0,1209,224,1290" href="" alt="imgmap201293016112-21" title="imgmap201293016112-21" class="imgmap201293016112-area" id="imgmap201293016112-area-21" />     <area shape="rect" coords="0,1290,225,1432" href="" alt="imgmap201293016112-22" title="imgmap201293016112-22" class="imgmap201293016112-area" id="imgmap201293016112-area-22" />     <area shape="rect" coords="0,1432,340,1517" href="" alt="imgmap201293016112-23" title="imgmap201293016112-23" class="imgmap201293016112-area" id="imgmap201293016112-area-23" />     <area shape="rect" coords="346,1432,686,1517" href="" alt="imgmap201293016112-24" title="imgmap201293016112-24" class="imgmap201293016112-area" id="imgmap201293016112-area-24" />     <area shape="rect" coords="461,1266,686,1429" href="" alt="imgmap201293016112-25" title="imgmap201293016112-25" class="imgmap201293016112-area" id="imgmap201293016112-area-25" />     <area shape="rect" coords="230,1365,455,1430" href="" alt="imgmap201293016112-26" title="imgmap201293016112-26" class="imgmap201293016112-area" id="imgmap201293016112-area-26" />     <area shape="rect" coords="231,1291,457,1360" href="" alt="imgmap201293016112-27" title="imgmap201293016112-27" class="imgmap201293016112-area" id="imgmap201293016112-area-27" />     <area shape="rect" coords="230,1210,342,1289" href="" alt="imgmap201293016112-28" title="imgmap201293016112-28" class="imgmap201293016112-area" id="imgmap201293016112-area-28" />     <area shape="rect" coords="692,928,916,1016" href="" alt="imgmap201293016112-29" title="imgmap201293016112-29" class="imgmap201293016112-area" id="imgmap201293016112-area-29" />     <area shape="rect" coords="460,616,916,759" href="" alt="imgmap201293016112-30" title="imgmap201293016112-30" class="imgmap201293016112-area" id="imgmap201293016112-area-30" />     <area shape="rect" coords="693,1316,917,1518" href="" alt="imgmap201293016112-31" title="imgmap201293016112-31" class="imgmap201293016112-area" id="imgmap201293016112-area-31" />     <area shape="rect" coords="344,1150,572,1219" href="" alt="imgmap201293016112-32" title="imgmap201293016112-32" class="imgmap201293016112-area" id="imgmap201293016112-area-32" />     <area shape="rect" coords="693,1015,916,1171" href="" alt="imgmap201293016112-33" title="imgmap201293016112-33" class="imgmap201293016112-area" id="imgmap201293016112-area-33" />     <area shape="rect" coords="577,955,686,1032" href="" alt="imgmap201293016112-34" title="imgmap201293016112-34" class="imgmap201293016112-area" id="imgmap201293016112-area-34" />     <area shape="rect" coords="577,1036,687,1101" href="" alt="imgmap201293016112-35" title="imgmap201293016112-35" class="imgmap201293016112-area" id="imgmap201293016112-area-35" />     <area shape="rect" coords="576,1104,689,1172" href="" alt="imgmap201293016112-36" title="imgmap201293016112-36" class="imgmap201293016112-area" id="imgmap201293016112-area-36" />     <area shape="rect" coords="691,1232,918,1313" href="" alt="imgmap201293016112-37" title="imgmap201293016112-37" class="imgmap201293016112-area" id="imgmap201293016112-area-37" />     <area shape="rect" coords="341,1085,573,1151" href="" alt="imgmap201293016112-38" title="imgmap201293016112-38" class="imgmap201293016112-area" id="imgmap201293016112-area-38" />     <area shape="poly" coords="917,868,917,925,688,927,688,955,576,955,574,867,572,864" href="" alt="imgmap201293016112-39" title="imgmap201293016112-39" class="imgmap201293016112-area" id="imgmap201293016112-area-39" />     <area shape="poly" coords="919,1173,917,1231,688,1231,688,1266,574,1267,576,1175,576,1175" href="" alt="imgmap201293016112-40" title="imgmap201293016112-40" class="imgmap201293016112-area" id="imgmap201293016112-area-40" />     <area shape="poly" coords="572,1222,572,1265,459,1265,458,1289,339,1290,344,1225" href="" alt="imgmap201293016112-41" title="imgmap201293016112-41" class="imgmap201293016112-area" id="imgmap201293016112-area-41" /> </map> 

So how is it possible that when I hover the area, its border color turns to black or even red?

Answer 1

What I did was to create a canvas element that I then position in front of the image map. Then, whenever an area is moused-over, I call a func that gets the coord string for that shape and the shape-type. If it's a poly I use the coords to draw an outline on the canvas. If it's a rect I draw a rect outline. You could easily add code to deal with circles.

You could also set the opacity of the canvas to less than 100% before filling the poly/rect/circle. You could also change the reliance on a global for the canvas's context - this would mean you could deal with more than 1 image-map on the same page.

<!DOCTYPE html> <html> <head> <script>  // stores the device context of the canvas we use to draw the outlines // initialized in myInit, used in myHover and myLeave var hdc;  // shorthand func function byId(e){return document.getElementById(e);}  // takes a string that contains coords eg - "227,307,261,309, 339,354, 328,371, 240,331" // draws a line from each co-ord pair to the next - assumes starting point needs to be repeated as ending point. function drawPoly(coOrdStr) {     var mCoords = coOrdStr.split(',');     var i, n;     n = mCoords.length;      hdc.beginPath();     hdc.moveTo(mCoords[0], mCoords[1]);     for (i=2; i<n; i+=2)     {         hdc.lineTo(mCoords[i], mCoords[i+1]);     }     hdc.lineTo(mCoords[0], mCoords[1]);     hdc.stroke(); }  function drawRect(coOrdStr) {     var mCoords = coOrdStr.split(',');     var top, left, bot, right;     left = mCoords[0];     top = mCoords[1];     right = mCoords[2];     bot = mCoords[3];     hdc.strokeRect(left,top,right-left,bot-top);  }  function myHover(element) {     var hoveredElement = element;     var coordStr = element.getAttribute('coords');     var areaType = element.getAttribute('shape');      switch (areaType)     {         case 'polygon':         case 'poly':             drawPoly(coordStr);             break;          case 'rect':             drawRect(coordStr);     } }  function myLeave() {     var canvas = byId('myCanvas');     hdc.clearRect(0, 0, canvas.width, canvas.height); }  function myInit() {     // get the target image     var img = byId('img-imgmap201293016112');      var x,y, w,h;      // get it's position and width+height     x = img.offsetLeft;     y = img.offsetTop;     w = img.clientWidth;     h = img.clientHeight;      // move the canvas, so it's contained by the same parent as the image     var imgParent = img.parentNode;     var can = byId('myCanvas');     imgParent.appendChild(can);      // place the canvas in front of the image     can.style.zIndex = 1;      // position it over the image     can.style.left = x+'px';     can.style.top = y+'px';      // make same size as the image     can.setAttribute('width', w+'px');     can.setAttribute('height', h+'px');      // get it's context     hdc = can.getContext('2d');      // set the 'default' values for the colour/width of fill/stroke operations     hdc.fillStyle = 'red';     hdc.strokeStyle = 'red';     hdc.lineWidth = 2; } </script>  <style> body {     background-color: gray; } canvas {     pointer-events: none;       /* make the canvas transparent to the mouse - needed since canvas is position infront of image */     position: absolute; } </style>  <title></title> </head> <body onload='myInit()'>     <canvas id='myCanvas'></canvas>     <!-- gets re-positioned in myInit(); --> <center> <img src='http://dailyaeen.com.pk/epaper/wp-content/uploads/2012/09/27+Sep+2012-1.jpg?1349003469874' usemap='#imgmap_css_container_imgmap201293016112' class='imgmap_css_container' title='imgmap201293016112' alt='imgmap201293016112' id='img-imgmap201293016112' /> <map id='imgmap201293016112' name='imgmap_css_container_imgmap201293016112'>     <area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="2,0,604,-3,611,-3,611,166,346,165,345,130,-2,130,-2,124,1,128,1,126" href="" alt="imgmap201293016112-0" title="imgmap201293016112-0" class="imgmap201293016112-area" id="imgmap201293016112-area-0" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,131,341,213" href="" alt="imgmap201293016112-1" title="imgmap201293016112-1" class="imgmap201293016112-area" id="imgmap201293016112-area-1" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="346,166,614,241" href="" alt="imgmap201293016112-2" title="imgmap201293016112-2" class="imgmap201293016112-area" id="imgmap201293016112-area-2" />     <area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="917,242,344,239,345,496,574,495,575,435,917,433" href="" alt="imgmap201293016112-3" title="imgmap201293016112-3" class="imgmap201293016112-area" id="imgmap201293016112-area-3" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,416,341,494" href="" alt="imgmap201293016112-4" title="imgmap201293016112-4" class="imgmap201293016112-area" id="imgmap201293016112-area-4" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,215,341,410" href="" alt="imgmap201293016112-5" title="imgmap201293016112-5" class="imgmap201293016112-area" id="imgmap201293016112-area-5" />     <area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="916,533,916,436,578,436,576,495,806,496,807,535" href="" alt="imgmap201293016112-6" title="imgmap201293016112-6" class="imgmap201293016112-area" id="imgmap201293016112-area-6" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="805,536,918,614" href="" alt="imgmap201293016112-7" title="imgmap201293016112-7" class="imgmap201293016112-area" id="imgmap201293016112-area-7" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="461,494,803,616" href="" alt="imgmap201293016112-8" title="imgmap201293016112-8" class="imgmap201293016112-area" id="imgmap201293016112-area-8" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,497,223,616" href="" alt="imgmap201293016112-9" title="imgmap201293016112-9" class="imgmap201293016112-area" id="imgmap201293016112-area-9" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="230,494,456,614" href="" alt="imgmap201293016112-10" title="imgmap201293016112-10" class="imgmap201293016112-area" id="imgmap201293016112-area-10" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="345,935,572,1082" href="" alt="imgmap201293016112-11" title="imgmap201293016112-11" class="imgmap201293016112-area" id="imgmap201293016112-area-11" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,617,457,760" href="" alt="imgmap201293016112-12" title="imgmap201293016112-12" class="imgmap201293016112-area" id="imgmap201293016112-area-12" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="345,760,577,847" href="" alt="imgmap201293016112-13" title="imgmap201293016112-13" class="imgmap201293016112-area" id="imgmap201293016112-area-13" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,759,344,906" href="" alt="imgmap201293016112-14" title="imgmap201293016112-14" class="imgmap201293016112-area" id="imgmap201293016112-area-14" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="346,850,571,935" href="" alt="imgmap201293016112-15" title="imgmap201293016112-15" class="imgmap201293016112-area" id="imgmap201293016112-area-15" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="578,761,915,865" href="" alt="imgmap201293016112-16" title="imgmap201293016112-16" class="imgmap201293016112-area" id="imgmap201293016112-area-16" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1017,226,1085" href="" alt="imgmap201293016112-17" title="imgmap201293016112-17" class="imgmap201293016112-area" id="imgmap201293016112-area-17" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,908,342,1017" href="" alt="imgmap201293016112-18" title="imgmap201293016112-18" class="imgmap201293016112-area" id="imgmap201293016112-area-18" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="229,1010,342,1084" href="" alt="imgmap201293016112-19" title="imgmap201293016112-19" class="imgmap201293016112-area" id="imgmap201293016112-area-19" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1086,340,1206" href="" alt="imgmap201293016112-20" title="imgmap201293016112-20" class="imgmap201293016112-area" id="imgmap201293016112-area-20" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1209,224,1290" href="" alt="imgmap201293016112-21" title="imgmap201293016112-21" class="imgmap201293016112-area" id="imgmap201293016112-area-21" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1290,225,1432" href="" alt="imgmap201293016112-22" title="imgmap201293016112-22" class="imgmap201293016112-area" id="imgmap201293016112-area-22" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1432,340,1517" href="" alt="imgmap201293016112-23" title="imgmap201293016112-23" class="imgmap201293016112-area" id="imgmap201293016112-area-23" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="346,1432,686,1517" href="" alt="imgmap201293016112-24" title="imgmap201293016112-24" class="imgmap201293016112-area" id="imgmap201293016112-area-24" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="461,1266,686,1429" href="" alt="imgmap201293016112-25" title="imgmap201293016112-25" class="imgmap201293016112-area" id="imgmap201293016112-area-25" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="230,1365,455,1430" href="" alt="imgmap201293016112-26" title="imgmap201293016112-26" class="imgmap201293016112-area" id="imgmap201293016112-area-26" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="231,1291,457,1360" href="" alt="imgmap201293016112-27" title="imgmap201293016112-27" class="imgmap201293016112-area" id="imgmap201293016112-area-27" />     <area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="230,1210,342,1289" href="" 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