Web Front-end
JS Tutorial
JavaScript method to determine browsing device based on CSS Media Queries_javascript skills
JavaScript method to determine browsing device based on CSS Media Queries_javascript skills
css section
first, create a new class for making judgments, and then use media queries to assign different values to the z-index attribute of this class. this class is only used for javascript reading, so it needs to be moved out of the screen window and invisible to the viewer to avoid unexpected situations.
as a demonstration, the following code sets four device states: regular desktop version, small screen desktop version, tablet version, and mobile version.
/* default state */
.state-indicator {
position: absolute;
top: -999em;
left: -999em;
z-index: 1;
}
/* small desktop */
@media all and (max-width: 1200px) {
.state-indicator {
z-index: 2;
}
}
/* tablet */
@media all and (max-width: 1024px) {
.state-indicator {
z-index: 3;
}
}
/* mobile phone */
@media all and (max-width: 768px) {
.state-indicator {
z-index: 4;
}
}
javascript judgment
css is already in place, so you need to use javascript to generate a temporary dom object, then set the corresponding class for it, and then read the z-index value of this object. the original writing method is as follows:
// create the state-indicator element
var indicator = document.createelement('div');
indicator.classname = 'state-indicator';
document.body.appendchild(indicator);
// create a method which returns device state
function getdevicestate() {
return parseint(window.getcomputedstyle(indicator).getpropertyvalue('z-index'), 10);
}
getdevicestate() 函数返回的就是 z-index 的值，为了增强一下可读性，可以用 switch 函数来规范输出一下：
function getdevicestate() {
switch(parseint(window.getcomputedstyle(indicator).getpropertyvalue('z-index'), 10)) {
case 2:
return 'small-desktop';
break;
case 3:
return 'tablet';
break;
case 4:
return 'phone';
break;
default:
return 'desktop';
break;
}
}
in this way, you can use the following code to determine the device status, and then execute the corresponding javascript code:
if(getdevicestate() == 'tablet') {
// 平板电脑下执行的 javascript 代码
}
if you are using jquery here, just use the following code:
$(function(){
$('body').append('<div class="state-indicator"></div>');
function getDeviceState() {
switch(parseInt($('.state-indicator').css('z-index'),10)) {
case 2:
return 'small-desktop';
break;
case 3:
return 'tablet';
break;
case 4:
return 'phone';
break;
default:
return 'desktop';
break;
}
}
console.log(getDeviceState());
$('.state-indicator').remove();
});
first create, then obtain, and finally delete the node. the specific device will be output in your console, click here to view demo . you can try dragging the middle border and click run.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1393
52
1205
24
How to use bootstrap in vue
Apr 07, 2025 pm 11:33 PM
Using Bootstrap in Vue.js is divided into five steps: Install Bootstrap. Import Bootstrap in main.js. Use the Bootstrap component directly in the template. Optional: Custom style. Optional: Use plug-ins.
The Roles of HTML, CSS, and JavaScript: Core Responsibilities
Apr 08, 2025 pm 07:05 PM
HTML defines the web structure, CSS is responsible for style and layout, and JavaScript gives dynamic interaction. The three perform their duties in web development and jointly build a colorful website.
How to write split lines on bootstrap
Apr 07, 2025 pm 03:12 PM
There are two ways to create a Bootstrap split line: using the tag, which creates a horizontal split line. Use the CSS border property to create custom style split lines.
Understanding HTML, CSS, and JavaScript: A Beginner's Guide
Apr 12, 2025 am 12:02 AM
WebdevelopmentreliesonHTML,CSS,andJavaScript:1)HTMLstructurescontent,2)CSSstylesit,and3)JavaScriptaddsinteractivity,formingthebasisofmodernwebexperiences.
How to use bootstrap button
Apr 07, 2025 pm 03:09 PM
How to use the Bootstrap button? Introduce Bootstrap CSS to create button elements and add Bootstrap button class to add button text
How to set up the framework for bootstrap
Apr 07, 2025 pm 03:27 PM
To set up the Bootstrap framework, you need to follow these steps: 1. Reference the Bootstrap file via CDN; 2. Download and host the file on your own server; 3. Include the Bootstrap file in HTML; 4. Compile Sass/Less as needed; 5. Import a custom file (optional). Once setup is complete, you can use Bootstrap's grid systems, components, and styles to create responsive websites and applications.
How to insert pictures on bootstrap
Apr 07, 2025 pm 03:30 PM
There are several ways to insert images in Bootstrap: insert images directly, using the HTML img tag. With the Bootstrap image component, you can provide responsive images and more styles. Set the image size, use the img-fluid class to make the image adaptable. Set the border, using the img-bordered class. Set the rounded corners and use the img-rounded class. Set the shadow, use the shadow class. Resize and position the image, using CSS style. Using the background image, use the background-image CSS property.
How to resize bootstrap
Apr 07, 2025 pm 03:18 PM
To adjust the size of elements in Bootstrap, you can use the dimension class, which includes: adjusting width: .col-, .w-, .mw-adjust height: .h-, .min-h-, .max-h-
