Use jQuery code snippet to find the highest z-index value of an absolutely positioned div. This is useful for making new elements absolutely appear on top of all HTML elements.

//包含 jQuery.js -- 訪問：http://jquery.com/
$(function(){
    var maxZ = Math.max.apply(null,$.map($('body > *'), function(e,n){
           if($(e).css('position')=='absolute')
                return parseInt($(e).css('z-index'))||1 ;
           })
    );
    alert(maxZ);
});

jQuery and Z-index FAQ (FAQ)

How to use jQuery to find the highest Z-index value on a page?

To use jQuery to find the highest Z-index value on the page, you can use the .css() method to get the Z-index value of each element and compare them to find the highest one. Here is a simple code snippet:

var highestZIndex = 0;
$("*").each(function() {
  var currentZIndex = parseInt($(this).css("z-index"), 10);
  if (currentZIndex > highestZIndex) {
    highestZIndex = currentZIndex;
  }
});
console.log(highestZIndex);

This code will record the highest Z-index value to the console.

What is the role of Z-index in jQuery?

In jQuery, Z-index is used to specify the stacking order of elements. Elements with higher Z-index values ??are always ahead of elements with lower Z-index values. This is especially useful when you have overlapping elements and want to control which element should be on top.

How to set the Z-index of an element using jQuery?

You can set the Z-index of an element using the .css() method in jQuery. Here is an example:

$("#myElement").css("z-index", 9999);

This sets the Z-index of the element with ID "myElement" to 9999.

Can I use negative Z-index values ??in jQuery?

Yes, you can use negative Z-index values ??in jQuery. A negative Z-index value means that the element will be placed after another element with Z-index 0 or greater.

How does Z-index work with positioning elements in jQuery?

Z-index attribute is only applicable to positioning elements (position: absolute, position: relative or position: fixed). If the position property is static (default), the Z-index property is invalid.

What happens if two elements have the same Z-index?

If two elements have the same Z-index, the elements that appear after HTML will be displayed at the top.

How to use jQuery to find Z-index for a specific element?

You can use the .css() method in jQuery to find the Z-index of a specific element. Here is an example:

var zIndex = $("#myElement").css("z-index");
console.log(zIndex);

This records the Z-index of the element with ID "myElement" to the console.

Can I use the Z-index attribute with non-localized elements?

No, the Z-index attribute is only applicable to positioning elements. If the element is not positioned, the Z-index property is invalid.

How to use jQuery to add Z-index to an element?

You can use the .css() method in jQuery to add the Z-index of the element. Here is an example:

var currentZIndex = parseInt($("#myElement").css("z-index"), 10);
$("#myElement").css("z-index", currentZIndex + 1);

This increases the Z-index of the element with ID "myElement" by 1.

Can I use the Z-index attribute with the animate() method in jQuery?

No, the Z-index attribute cannot be animation using jQuery's animate() method. The animate() method can only be used for properties with numeric properties, while the Z-index property has no numeric values.

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