How can I create a dropdown menu in the hero section of a Webflow website that is preselected based on the ad that brought the user there?

To create a preselected dropdown menu in the hero section of your Webflow website, you will need to utilize Webflow's built-in form element and custom code functionality. Here's a step-by-step guide on how to achieve this:

Step 1: Set up a dropdown menu
- Add a form element to your hero section by dragging and dropping the "Form" component from the Add panel.
- Inside the form element, drag and drop a "Select field" (dropdown) from the Add panel.
- Double-click the select field to open its settings panel on the right.
- Expand the "Option 1" section and provide a label and value for the option. Repeat this for any additional options you want to include in the dropdown.

Step 2: Add custom code to preselect the dropdown option
- Select the hero section and go to the Settings panel on the right.
- Scroll down to the "Custom Code" section and click the "Before " tab.
- In the custom code field, you can write JavaScript logic to preselect the dropdown option based on the ad that brought the user there.

Here's an example code snippet assuming you have a URL parameter `ad` that holds the value of the ad:

```javascript

```

Replace `.your-dropdown-class` with the actual class or ID of your dropdown element, and make sure to adjust the URL parameter name and the comparison logic (`option.value === ad`) based on how your ad URL parameter is structured.

Step 3: Publish and test
- Once you have added the custom code, you can publish the site to see the dropdown preselected based on the ad parameter in the URL.
- Test it by opening different ad URLs and verifying if the appropriate dropdown option is preselected.

By combining the use of Webflow's form element with custom code, you can dynamically preselect a dropdown option based on the ad that brought the user to your website.