To change the visibility of each individual layer of a map service, you need to work with the ArcGISDynamicMapServiceLayer.setVisibleLayers() method. Here is a sample I put together to demonstrate how to toggle the visibility of each individual layer of a map service by using check box. Hope this helps to get you start.<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=7,IE=9" />
<!--The viewport meta tag is used to improve the presentation and behavior of the samples
on iOS devices-->
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no"/>
<title>Updating the legend to display visible layers</title>
<link rel="stylesheet" type="text/css" href="http://serverapi.arcgisonline.com/jsapi/arcgis/3.0/js/dojo/dijit/themes/claro/claro.css">
<style>
html, body { height: 98%; width: 98%; margin: 0; padding: 5px; }
#rightPane{
width:20%;
}
#legendPane{
border: solid #97DCF2 1px;
}
</style>
<script type="text/javascript">var djConfig = {parseOnLoad: true};</script>
<script type="text/javascript" src="http://serverapi.arcgisonline.com/jsapi/arcgis/?v=3.0"></script>
<script type="text/javascript">
dojo.require("dijit.layout.BorderContainer");
dojo.require("dijit.layout.ContentPane");
dojo.require("dijit.layout.AccordionContainer");
dojo.require("esri.map");
dojo.require("esri.dijit.Legend");
dojo.require("esri.arcgis.utils");
dojo.require("dijit.form.CheckBox");
var map;
var legendLayers = [];
var legendLayer;
function init() {
var initialExtent = new esri.geometry.Extent({"xmin":-117.98,"ymin":33.95,"xmax":-116.92,"ymax":34.44,"spatialReference":{"wkid":4326}});
map = new esri.Map("map", { extent: esri.geometry.geographicToWebMercator(initialExtent)});
//Add the terrain service to the map. View the ArcGIS Online site for services http://arcgisonline/home/search.html?t=content&f=typekeywords:service
var basemap = new esri.layers.ArcGISTiledMapServiceLayer("http://server.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer");
map.addLayer(basemap);
var quakeLayer = new esri.layers.ArcGISDynamicMapServiceLayer("http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Earthquakes/EarthquakesFromLastSevenDays/MapServer",{id:'quakes'});
legendLayers.push({layer:quakeLayer,title:'Earthquakes'});
var fireLayer = new esri.layers.ArcGISDynamicMapServiceLayer("http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Fire/Sheep/MapServer",{id:'fire'});
legendLayers.push({layer:fireLayer,title:"Fire"});
dojo.connect(map,'onLayersAddResult',function(results){
var legend = new esri.dijit.Legend({
map:map,
layerInfos:legendLayers
},"legendDiv");
legend.startup();
});
map.addLayers([fireLayer,quakeLayer]);
dojo.connect(map,'onLayersAddResult',function(results){
var layerLists=[];
dojo.forEach(legendLayers,function(layer){
layerLists.push(buildLayerList(layer));
});
dojo.byId("layer_list").innerHTML = layerLists.join('');
});
dojo.connect(map, 'onLoad', function(theMap) {
//resize the map when the browser resizes
dojo.connect(dijit.byId('map'), 'resize', map,map.resize);
});
}
function buildLayerList(layer) {
var visible = [];
var items = dojo.map(layer.layer.layerInfos,function(info,index){
if (info.defaultVisibility) {
visible.push(info.id);
}
return "<input type='checkbox' class='" + layer.title + "' checked='true' id='" + info.id + "' onclick='updateLayerVisibility();' /><label for='" + info.id + "'>" + info.name + "</label><br>";
});
layer.layer.setVisibleLayers(visible);
return items.join(' ');
}
function updateLayerVisibility() {
dojo.forEach(legendLayers,function(layer){
var inputs = dojo.query("."+ layer.title), input;
var visible = [];
dojo.forEach(inputs,function(input){
if (input.checked) {
visible.push(input.id);
}
});
//if there aren't any layers visible set the array to be -1
if(visible.length === 0){
visible.push(-1);
}
layer.layer.setVisibleLayers(visible);
});
}
dojo.addOnLoad(init);
</script>
</head>
<body class="claro">
<div id="content" dojotype="dijit.layout.BorderContainer" design="headline" gutters="true" style="width: 100%; height: 100%; margin: 0;">
<div id="rightPane" dojotype="dijit.layout.ContentPane" region="right">
<div dojoType="dijit.layout.AccordionContainer">
<div dojoType="dijit.layout.ContentPane" id="legendPane" title="Legend" selected="true">
<div id="legendDiv"></div>
</div>
<div dojoType="dijit.layout.ContentPane" title="Natural Disasters" >
<span style="padding:10px 0;" id="layer_list"></span>
<div id="toggle" style="padding: 2px 2px;"></div>
</div>
</div>
</div>
<div id="map" dojotype="dijit.layout.ContentPane" region="center" style="overflow:hidden;">
</div>
</div>
</body>
</html>
