To make text appear when hovering over a div, you can use CSS and apply the :hover pseudo-class to the div element. Here's an example:

HTML:

html
 
 
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<div class="hover-div">Hover over me</div>

CSS:

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.hover-div {
  position: relative;
}

.hover-div::after {
  content: "Text that appears on hover";
  position: absolute;
  top: 100%;
  left: 0;
  visibility: hidden;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.hover-div:hover::after {
  visibility: visible;
  opacity: 1;
}

In this example, the text is added as a pseudo-element (::after) of the div. The visibility and opacity properties are initially set to hidden and 0, respectively, so the text is not visible. When the div is hovered over, the visibility and opacity properties are changed to visible and 1, respectively, making the text appear.

You can adjust the appearance of the text by modifying the CSS properties in the example code.

In CSS, the visibility: hidden property is used to hide an element without affecting the layout of the webpage. When an element is set to visibility: hidden, it becomes invisible but still takes up space on the webpage. This means that even though you can't see the element, it will still affect the positioning of other elements around it.

Here's an example of how to use visibility: hidden in CSS:

css
 
 
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.hidden-element {
  visibility: hidden;
}

You can apply this class to an HTML element to hide it from view.

HTML:

html
 
 
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<input type="file" id="inputFile"/>

CSS:

css
 
 
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#inputFile::-webkit-file-upload-button {
  visibility: hidden;
}

JavaScript:

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document.getElementById("inputFile").addEventListener("change", function() {
  if (this.value) {
    this.setAttribute("data-title", this.value.replace(/^.*[\\\/]/, ''));
  } else {
    this.setAttribute("data-title", "No file chosen");
  }
});

To make a div visible only on mobile, you can use the @media attribute in CSS. Here is an example in SCSS:

scss
 
 
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@media screen and (max-width: 480px) { 
  div { 
    display: block; 
  } 
}

This code will make the div visibility only on screens with width of 480px or less. You can adjust the numbers to suit your project. For further reading about the @media attribute, checkout MDN's documentation.

Yes, you can have multiple <h1> tags on a single page; however, it is generally not recommended. Having multiple <h1> tags on the same page can be confusing for search engine crawlers and can create poor SEO visibility overall. To avoid this, use <h2-h6> tags for headers after the main <h1> tag. See this article for more information.

SEO, or search engine optimization, is the process of improving a website’s visibility and usability for users and search engine robots. Optimizing a website for SEO can be done by improving website speed, utilizing descriptive metadata, using keywords throughout the content, using structured data, and optimizing visual media. To learn more about SEO and how to optimize your website, check out Google’s Search Engine Optimization Starter Guide.