Hi Jinny,
in order to "play" with it, you'll have to
)load miserver ⍝ recommandation: get the latest
Start'./MS3' ⍝ or any other site
The _-namespace is not a part of MiServer.dws (which explains your trouble finding it) - it is created dynamically when you start a site.
In response to the Start-Command, MiServer will spit out something like "MiServer for "./MS3" started on
http://192.168.178.25:8080". Simply Ctrl+Click on the http:-address to open the site in your browser. Click on the "Samples"-tab to see a list of available controls and sample-code for them. There is a Search- Box into which you can type keywords describing a feature that you look for...and the list will be reduced to matching items as you type. Click on any sample to open the page. In the right part of the top-navigation of every sample page (even the list of controls!) you can always click the "View"-menu and select "APL Code" to inspect the code that created this page.
Alternatively, you can also do some interactive exploration in the APL-Session once MiServer has been started with a page (again: "Start" is neccessary to invoque all required classes...).
Basic example:
p←#.HtmlElement.New _.i 'Hello World'
p.Render
<i>Hello World</i>
Playing with it:
p←#.HtmlElement.New _.div ⍝ create an empty <div>-tag
p.Render ⍝ verify!
<div></div>
p.Add _.b 'Hello World!' ⍝ Add to it
p.Add _.i 'I like Dyalog APL!' ⍝ I hope so ;-)
p.Render ⍝ verify!
<div><b>Hello World!</b><i>I like Dyalog APL!</i></div>
'#wow'p.Add _.p 'Jawdropping example' 'style=font-size:huge;' ⍝ define attributes while adding element!
p.Render ⍝ verify!
<div><b>Hello World!</b><i>I like Dyalog APL!</i><p id="wow" style="font-size:huge;">Jawdropping example</p></div>
I hope this provides some inspiration for your own experiments ;-)