What parameters can be used with
.../MapServer?f=jsapi to alter the results, like turning on or off a single layer?
This leads to a light-weight web map with minimal chrome, widgets, etc. and no reliance on a 3rd party server like ArcGIS Online to draw the results. It is really handy for having a quick look at the service, with a bonus of having a shareable URL that anyone can see.
The problem, from my present perspective, is that the view is limited to the default definition in the MapServer service definition. In this soil survey example there are 3 layers in the MapServer. What I'd like to be able to do is use the same minimal-chrome webmap to view just one of those layers, not the whole map.
This Soils Survey isn't the best example of my dilemma since the desired layer will draw at the appropriate zoom level. The circumstance which prompted this question is a map service that has layers turned off by default. I can use ArcGIS Online's Use URL parameters to modify maps
&layers=show:2,4 to fix that, but that invokes overhead and complexity I'm trying to avoid (using multiple servers and services for mere data viewing).