Hi there!
Well I can't answer for the visu stuff... but taking a look into the information you sent:
1) On the JS Pre Apply, it seems to me that you are taking the value of the custom parameter id 0 and storing it into Stack. And then, you are raising the stack and applying the Stack value into the parameter id 0. On my way of seing things, what are you doing is just increasing the custom parameter id 0 value to +10, right? And that happens when you apply the state.
2) Don't know what slip dagame is, but it seems that when the state expires or erases, you are setting the custom parameter id 0 value to 0.
3) I don't know if this is a problem, but avoid using the shortname as the template name. Put something different on the template name.
4) Unexpected identifier is kinda like a javascript formula error. You wrote down something that is not valid javascript. For your screenshot, I presume it would be that part:
if Burning = false
{
Use.setCustomParam(0,0)
}
I guess what are you trying to do is:
if(Burning === false){
User.setCustomParam(0,0)
}
if statements need to be around parenthesis. And to compare values you must use == or ===. Just one =, means an assignment, not a comparison. I suggest you taking a look here:
https://www.w3schools.com/jsref/jsref_if.asp
5) Now I see that said that the main problem is that you are not being able to reset the custom parameter to 0. As far as I can see, your formulas should work regarding using my plugin. Here is a screenshot of me doing something like you did. I guess maybe the problem is something on the visustella note tags flow.
Let me know if I understood you properly.
Either way, you may have better luck using my Dynamic Parameter plugin to change the custom parameter value:
Hakuen Studio Dynamic Parameters for RPG Maker MZ by Hakuen Studio
You can just add a note tag into a state that will change the custom parameter value when the battler is with the state. And will automatically remove when the battler loses that state. Just by using this note tag on the state:
<DynCParam dot> return 10 </DynCParam>
From your setup, I guess you just need to keep the `JS HP Slip Damage`. The other note tags from visu you won't need, if you use the Dynamic Parameter plugin like the above.
let me know the results!