That is because you "kill" the document when you do document.write(query). Look at the documentation of document.write.
This works:
@name = "the name"
@description = "the description"
dialog = UI;;WebDialog.new("Details", true, "sachi_pluginname_dialogname", 410, 875, 1030, 0, true)
dialog.add_action_callback("pass_data") { |dialog, htmlpage|
js = "set_details(#{@name.inspect}, #{@description.inspect})" # It's not java.
dialog.execute_script(js)
}
dialog.set_file 'C;\Program Files\Google\Google SketchUp 8\Plugins\set_id\details.html'
dialog.show()
<html>
<head>
<script>
function callRuby(htmlpage) {
// Declare the variable with "var" so that it is not global.
var query = 'skp;pass_data@' + htmlpage;
window.location.href = query;
}
function set_details(a, b){alert(a);
// Example 1
var text = document.createTextNode(a);
document.getElementById("detail1").appendChild(text);
// Alternative
// document.getElementById("detail1").innerHTML = a;
// Example 2
document.getElementById("detail2").value = b;
}
</script>
</head>
<body>
<div id="detail1"></div>
<input id="detail2" />
</body>
<script>
// If you will access element in the page, you need to do this after the page (body) has loaded.
callRuby("pull_selection_count");
</script>
</html>
