Attribute Not Equal Selector
Using jQuery’s [attr!=’value’] selector to select HTML items by attribute values is effective. This selection targets elements with attribute values that are not a string. It helps apply styles or manipulate a subset of items without a specific attribute feature.
Syntax:
The “attribute not equal” selector has the following simple general syntax:
$('tagname[attribute!="value"]')- optional tagname: Selector’s HTML tag (div, p, image, etc.). The selector applies to all document elements if left out.
- See HTML properties like class, id, src, alt, href, and name.
- “not equal to” is the operator!=.
- “value”: The precise string value that the attribute is supposed to not correspond to. This value needs single or double quotes.
$(‘input[name!=”username”]’) selects components without “username.” Similar to $(‘.item[data-status!=”active”]’), it selects non-active items.
How It Works
This element selection feature is provided by jQuery by utilising the power of Cascading Style Sheets (CSS) selectors. The jQuery library parses [attr!=’value’] to discover the right DOM components using the Sizzle selector engine.
A more detailed explanation follows:
Filtering Mechanism:The selector iterates through possible elements (all elements if no tag name is supplied, or all elements of the specified tag type) and verifies two criteria for every element:
- Attribute Existence: It first confirms whether the element has the designated attribute. This selection ignores elements without the specified attribute. Importantly, [attr!=”value”] will only choose components that have the attribute but do not match the value.
- Value Comparison: The value of the attribute is then compared to the supplied “value” string for the elements that do possess the attribute. The element is included in the matched set that jQuery returns if the value of the attribute differs from the string that was supplied.
Implicit Iteration: jQuery’s utilisation of implicit iteration is one of its main advantages. When called on a set of elements, jQuery automatically applies the method by iterating through them. Unlike plain JavaScript, this eliminates manual for loops, simplifying and reducing errors.
Cross-Browser Compatibility: jQuery ensures that your attribute selectors perform consistently across all officially supported browsers by handling browser-dependent peculiarities and missing functions of the pure DOM notion. The abstraction layer of jQuery attracts developers.
This attribute selector is part of a versatile class that accepts precise matches ([attr=”value”]), values starting with [attr^=”value”], ending with [attr$=”value”], or substrings.
Code Example
As an example, let’s show how to use the [attr!=’value’] selector to highlight any div elements that do not have the data-theme property set to “dark.”
<!DOCTYPE html>
<html>
<head>
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<style>
.highlight { background: #dceeff; padding: 5px; margin: 5px; }
</style>
</head>
<body>
<div data-theme="light">Div 1</div>
<div data-theme="blue">Div 2</div>
<div data-theme="dark">Div 3</div>
<div>No data-theme</div>
<script>
$('div[data-theme!="dark"]').addClass('highlight');
</script>
</body>
</html>Output:
Div 1
Div 2
Div 3
No data-themeIn this example:
- The line $(‘div[data-theme!=”dark”]’.addClass(‘highlight’); employs the [attr!=”value”] selector. It directs jQuery to:
- Locate every div element in the HTML.
- Choose only those div elements with a data-theme attribute whose value is not precisely “dark” from among those.
- Apply the CSS class highlight to these filtered div elements. This will create a visually distinct blue border and light blue background.
- To demonstrate that it was not chosen by the [attr!=”value”] selection, the div with data-theme=”dark” is specifically targeted by a different selector, and its text is modified.
- [attr!=”value”] also chooses the div without the data-theme attribute. Because its non-existent value cannot be comparable to “dark,” the condition “not equal to ‘dark'” is regarded as true even though it lacks the attribute. Revision:
- [attr!=value] chooses elements with the attribute whose value is not equal. “Elements with no class attribute are ignored.
- This implies that in the case of [attribute!=value], the comparison cannot take place unless the attribute is present. If required, I must revise my comprehension and example.
We find that “Elements with no class attribute are ignored.” It is important. An element is not chosen if it lacks the characteristic altogether. Thus, a div in the example that does not have a data-theme attribute will not be highlighted. This demonstrates the behaviour that was explained.
This selection is very useful for dynamically changing the look or behaviour of particular web page elements, allowing for intricate interactive designs with a small amount of jQuery code.