How to launch and show Salesforce Embedded Service Chat only on Button Click?

embedded_svc.settings.displayHelpButton = false code can be used to hide the Chat.

embedded_svc.liveAgentAPI.startChat() can be used to initiate the Chat.

When the visitor closes the Chat, it will be hidden since embedded_svc.settings.displayHelpButton = false code will hide the Chat.

Sample Code:

<html>
  <input type="button" value="Start Chat" onclick="startChat();" />
  <br />
  <br />
  <br />
  <!--
      Embedded Service Deployment Code Snippet.
      Also, add the following under var initESW = function(gslbBaseURL) code
      embedded_svc.settings.displayHelpButton = false;
  -->
  <script>
    function startChat() {
      console.log('Inside Start Chat');
      embedded_svc.liveAgentAPI.startChat({
        directToAgentRouting: {
          buttonId: "5735f000000Tm6g",
          fallback: true
        },
        extraPrechatInfo: [],
        extraPrechatFormDetails: []
      });
    }
  </script>
</html>