javascript 检查变量是否与 jquery 相等
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Check whether variables are equal with jquery
提问by salmon
Hey i am new to jquery and i was wondering whether someone could give me some help when it comes to working with variables. The below is what i have thus far. I want to find a certain divs left position and width and then do some basic maths with those variables. Sorry is this explanation is a little confusing. So just a example as to how i would create a variable from a divs width and how to check whether variables are equal to one another would be great.
嘿，我是 jquery 的新手，我想知道在使用变量时是否有人可以给我一些帮助。以下是我迄今为止所拥有的。我想找到某个 div 的左位置和宽度，然后用这些变量做一些基本的数学运算。抱歉，这个解释有点混乱。因此，仅举一个关于如何从 div 宽度创建变量以及如何检查变量是否彼此相等的示例会很棒。
$(document).ready(function(){
//Check distance from left
var p = $(".GalleryItem");
var position = p.position();
$(".LeftPosition").text( "left: " + position.left + ", top: " + position.top );
//Check width of GalleryItem
var GalleryContainer = $(".GalleryItem");
$(".WidthText").text( "innerWidth:" + GalleryContainer.innerWidth() );
//Check width of Gallery
var GalleryContainer = $("#Gallery");
$(".WidthGalleryText").text( "innerWidth:" + GalleryContainer.innerWidth() );
});
回答by PJP
I guess you could just do something like:
我想你可以这样做：
var galleryItemWidth = $(".GalleryItem").innerWidth();
var galleryWidth = $("#Gallery").innerWidth();
And then just check something like this:
然后只需检查如下内容：
if (galleryItemWidth == galleryWidth) {
// Do something
}
else {
// Do something else
}
Or maybe I misunderstood your question?
或者我误解了你的问题？
回答by clumsyfingers
The .width() function is "recommended when width needs to be used in a mathematical calculation". It also covers windows and document rather than just divs.
.width() 函数是“当需要在数学计算中使用宽度时推荐使用”。它还涵盖窗口和文档，而不仅仅是 div。
var position = $('.GalleryItem').position();
var galleryItemLeft = position.left;
var galleryItemWidth = $('.GalleryItem').width();
var galleryWidth = $('#Gallery').width();
// do calculations such as
var galleryItemRight = galleryItemLeft + galleryItemWidth;
// check if one width = another
if(galleryItemWidth == galleryWidth) { ... }
For jQuery, working with return values is just like working with any return value in javascript. Set a var = to the function (expecting a return value), compare with the '==' operator. In jQuery you can also set the actual selector objects to variables as you have done with 'var p = $('.GalleryItem');' To compare selector objects you would compare them by their properties, such as position, width, color, etc.
对于 jQuery，处理返回值就像处理 JavaScript 中的任何返回值一样。将 var = 设置为函数（期望返回值），与 '==' 运算符进行比较。在 jQuery 中，您还可以像使用 'var p = $('.GalleryItem');' 那样将实际的选择器对象设置为变量 要比较选择器对象，您可以通过它们的属性（例如位置、宽度、颜色等）来比较它们。
Hope this helps.
希望这可以帮助。
