有没有办法用Javascript检测Bootstrap 4使用的视图端口/屏幕大小?
当用户调整浏览器大小时,我找不到可靠的方法来检测当前视图端口。我尝试过Bootstrap toolkit但它似乎与Bootstrap 4不兼容。
有人知道另一种方法吗?
看起来我们可以轻松调整Bootstrap工具包以使其与Bootstrap 4兼容,只需按照以下步骤操作:
// Bootstrap 3
bootstrap: {
'xs': $('<div class="device-xs visible-xs visible-xs-block"></div>'),
'sm': $('<div class="device-sm visible-sm visible-sm-block"></div>'),
'md': $('<div class="device-md visible-md visible-md-block"></div>'),
'lg': $('<div class="device-lg visible-lg visible-lg-block"></div>')
},
通过这个:
// Bootstrap 4
bootstrap: {
'xs': $('<div class="device-xs hidden-sm-up">xs</div>'),
'sm': $('<div class="device-sm hidden-xs-down hidden-md-up">sm</div>'),
'md': $('<div class="device-md hidden-sm-down hidden-lg-up">md</div>'),
'lg': $('<div class="device-lg hidden-xl-up hidden-md-down">lg</div>'),
'xl': $('<div class="device-lg hidden-lg-down">xl</div>')
}
然后您可以正常使用该工具包来检测屏幕大小:
// Wrap IIFE around your code
(function($, viewport){
$(document).ready(function() {
// Executes only in XS breakpoint
if(viewport.is('xs')) {
// ...
}
// Executes in SM, MD and LG breakpoints
if(viewport.is('>=sm')) {
// ...
}
// Executes in XS and SM breakpoints
if(viewport.is('<md')) {
// ...
}
// Execute code each time window size changes
$(window).resize(
viewport.changed(function() {
if(viewport.is('xs')) {
// ...
}
})
);
});
})(jQuery, ResponsiveBootstrapToolkit);
感谢Ander,让我走上正轨!但是我不得不用以下内容替换bootstrap-3-section:
// Bootstrap 4
bootstrap: {
'xs': $('<div class="device-xs d-block d-sm-none" ></div>'),
'sm': $('<div class="device-sm d-none d-sm-block d-md-none"></div>'),
'md': $('<div class="device-md d-none d-sm-none d-md-block d-lg-none"></div>'),
'lg': $('<div class="device-lg d-none d-sm-none d-md-none d-lg-block d-xl-none"></div>'),
'xl': $('<div class="device-lg d-none d-sm-none d-md-none d-lg-none d-xl-block"></div>')
}
从Bootstrap 4.2.x开始,我们没有其他任何答案,但以下工作方式如下:
// Bootstrap 4
bootstrap: {
'xs': $('<div class="device-xs d-block d-sm-none">xs</div>'),
'sm': $('<div class="device-sm d-none d-sm-block d-md-none">sm</div>'),
'md': $('<div class="device-md d-none d-md-block d-lg-none">md</div>'),
'lg': $('<div class="device-lg d-none d-lg-block d-xl-none">lg</div>'),
'xl': $('<div class="device-lg d-none d-xl-block">xl</div>')
}
我不太确定为什么所有答案都涉及将一个元素插入到DOM中以检查它是否会被显示? DOM操作很昂贵,为什么不直接读取视口宽度?
This S/O Question提供了阅读宽度的最佳方式。将其转换为引导程序宽度很容易:
function getViewport () {
// https://stackoverflow.com/a/8876069
const width = Math.max(
document.documentElement.clientWidth,
window.innerWidth || 0
)
if (width <= 576) return 'xs'
if (width <= 768) return 'sm'
if (width <= 992) return 'md'
if (width <= 1200) return 'lg'
return 'xl'
}
如果您希望每次视口更改时触发某种事件...
$(document).ready(function () {
let viewport = getViewport()
let debounce
$(window).resize(() => {
debounce = setTimeout(() => {
const currentViewport = getViewport()
if (currentViewport !== viewport) {
viewport = currentViewport
$(window).trigger('newViewport', viewport)
}
}, 500)
})
$(window).on('newViewport', (viewport) => {
// do something with viewport
})
// run when page loads
$(window).trigger('newViewport', viewport)
}