the plugin passC2Value allows you to pass a value from Construct to the parent html-site and vice versa. It's a little tricky and you should'nt be afraid of modifying html-code.
Info: The plugin will not do anything in the preview, because in the local preview aren't any for the plugin needed variables - see below.
Have a look at the Html-Source of the example sites. After exporting your project in Construct2 you have to modify your index.html:
0) open your index.html with a text-editor (ie: notepad, notepad++)
1) copy the Html-Source from an example site and paste it in your index.html => save the file
if ('more than one passC2Value-Plugin used' or 'changed the initial values of the plugin')
2) modify the variablenames as needed in the file index-html
(the variablenames are the initialvalues of the Plugin)
Have fun, Joe7