Option to cancel initial load for browser usage

[messizqin]

First cheers for making this awesome app. I am using less in browser environment, docs suppose to be https://lesscss.org/usage/#programmatic-usage, however, in the Browser Usage Option part, I failed to find a way to disable the initial loads, the doc referred

<!-- set options before less.js script -->
<script>
  less = {
    env: "development",
    logLevel: 2,
    async: false,
    fileAsync: false,
    poll: 1000,
    functions: {},
    dumpLineNumbers: "comments",
    relativeUrls: false,
    globalVars: {
      var1: '"quoted value"',
      var2: 'regular value'
    },
    rootpath: ":/a.com/"
  };
</script>
<script src="less.js"></script>

But I did not see the details of each option and their usage. Is there an option I can the lib’s initial attempt to compiling all dom less style sheet?