I'm missing something about scrollTrigger "start" and "scroll-start"

[gringo_pablo]

Hi,

 

I've read the docs carefully, but the animation I'm trying to create still misses something... 

Here's the demo: https://studio-format.webflow.io/projets

Whenever you click a Project's link, it opens the Project Page in the form of an Ajax Modal.

What I want to achieve, is that when the user makes the first scroll on this new page, the Navbar moves up to leave the whole space for the modal.

 

So my trigger is the wrapper inside the modal (the modal, or Lightbox, being position:fixed). When the top of it reaches the bottom of the navbar, I want the navbar to move its size up. 

 

let nav_h = document.querySelector(".navbar").offsetHeight
let height = nav_h - 5

gsap.to(".navbar", {
  scrollTrigger: {
    trigger: ".lightbox-modal-wrapper",
    start: "top " + height + "px",
    end: height + "px top",
    markers: true,
  },
  y: "-" + nav_h,
})

 

I used the markers in order to get some insights, and the weird thing is that the "start" marker doesn't move... I'm pretty sure it comes from the way my Modal is positioned according to the Navbar, but I can't figure it out.

 

[GSAP Helper]

It's pretty tough to troubleshoot without a minimal demo - the issue could be caused by CSS, markup, a third party library, your browser, an external script that's totally unrelated to GSAP, etc. Would you please provide a very simple CodePen or Stackblitz that demonstrates the issue? 

 

Please don't include your whole project. Just some colored <div> elements and the GSAP code is best. See if you can recreate the issue with as few dependancies as possible. If not, incrementally add code bit by bit until it breaks. Usually people solve their own issues during this process! If not, then at least we have a reduced test case which greatly increases your chances of getting a relevant answer.

 

Here's a starter CodePen that loads all the plugins. Just click "fork" at the bottom right and make your minimal demo: 

See the Pen aYYOdN by GreenSock (@GreenSock) on CodePen

 

Using a framework/library like React, Vue, Next, etc.? 

CodePen isn't always ideal for these tools, so here are some Stackblitz starter templates that you can fork and import the gsap-trial NPM package for using any of the bonus plugins: 

• React (please read this article!)
• Next
• Svelte
• Sveltekit
• Vue
• Nuxt

 

Please share the StackBlitz link directly to the file in question (where you've put the GSAP code) so we don't need to hunt through all the files. 

 

Once we see an isolated demo, we'll do our best to jump in and help with your GSAP-specific questions. 

[Rodrigo]

Hi @gringo_pablo and welcome to the GSAP forums!

 

Take a look at these examples for inspiration:

See the Pen qBawMGb by GreenSock (@GreenSock) on CodePen

 

See the Pen mdVyPvK by GreenSock (@GreenSock) on CodePen

 

Hopefully this helps.

Happy Tweening!

[gringo_pablo]

Thanks @Rodrigo, I'll have a look!