I use this on featureLayers but it basically adjusts the transparency option for the layer. It uses the dijit.form.HorizontalSlider.The HTML I have is:<p style="font-size:140%;margin-left: 10px">Use this slider to adjust the transparency of the Demographic Data Overlays:</p>
<div id="theOpacitySlider" dojoType="dijit.form.HorizontalSlider" name="horizontal1"
onChange="applyOpacity"
value="40"
maximum="100"
minimum="0"
discreteValues="11"
pageIncrement="100"
showButtons="false"
intermediateChanges="false"
slideDuration="500"
style="width:290px; height: 20px;margin-left:auto;margin-right:auto"
id="slider1">
<ol dojoType="dijit.form.HorizontalRuleLabels" container="topDecoration" style="height:1.2em;font-size:90%;font-weight:bold" count="6" numericMargin="0"></ol>
<div dojoType="dijit.form.HorizontalRule" container="topDecoration" count=11 style="height:5px;"></div>
<div id = "theOpacityRuler" dojoType="dijit.form.HorizontalRule" container="bottomDecoration" count=2 style="height:10px;"></div>
<ol dojoType="dijit.form.HorizontalRuleLabels" container="bottomDecoration" style="height:1em;font-size:90%;font-style:italic">
<li>Solid</li>
<li>Transparent</li>
</ol>
</div><br />
<table>
<tr>
<td><SPAN style="font-weight:bold">Current Transparency Setting: <input readonly id="sliderInput" size="2" value="40%" style="padding-left:5px"></SPAN></td>
</tr>
</table>
The javascript code is:function applyOpacity() {
var theAmount;
theAmount = arguments[0];
theOpacity = 1 - (theAmount / 100);
map.getLayer('your Layer ID here').setOpacity(theOpacity);
}
Be sure to also include the necessary dojo.requires:dojo.require("dijit.form.HorizontalSlider");
dojo.require("dijit.form.HorizontalRuleLabels");
dojo.require("dijit.form.HorizontalRule");
I also included a screenshot to give you an idea of what it looks like.Good luck!Steve