How do I Edit the HTML File before it has been exported wanna add a script ?
Develop games in your browser. Powerful, performant & highly capable.
Use the Addon SDK.
There's also this suggestion: construct3.ideas.aha.io/ideas/C3-I-305
When I have the spare time (he says, writing this at work...(!)) I will hopefully look into Ashley's suggestion of making an Addon, or perhaps hiring another dev to walk me through the steps; as just trying to read through the docs just doesn't click with me at the moment.
If anything comes of it I will let you know dineshiyer