Dynamically load css stylesheet and wait for it to load

问题

I have a script where I load a css stylesheet when pressing a button like this:

link = "<link class='listcss' rel='stylesheet' href='http://....list.css'>";
$("head").append(link);

Then I need to do some calculations based on the css width and height properties:

function CSSDone(){
            if($(window).width()>640){
                $(".grid-item").css({"height":$(".grid-item").width()*0.2});
                $(".grid_item_img").css({"height":$(".grid-item").width()*0.2});
            console.log("a");
            }else{
                $(".grid-item").css({"height":$(".grid-item").width()*0.33});
                $(".grid_item_img").css({"height":$(".grid-item").width()*0.33});
            console.log("b");       
            }
        }
        CSSDone();

However, if I launch CSSDone(); right after adding the stylesheet, the calculations happen before the css is loaded. I searched the web like crazy but everything I tried doesn't work:

I tried these options: 1) Does not work:

link.onload = function () {
    CSSDone();
}

2) Does not work:

    if (link.addEventListener) {
      link.addEventListener('load', function() {
        CSSDone();
      }, false);
    }

3) Does not work:

    link.onreadystatechange = function() {
      var state = link.readyState;
      if (state === 'loaded' || state === 'complete') {
        link.onreadystatechange = null;
        CSSDone();
      }
    };

4) Does not work:

    $(window).load(function () {
        CSSDone();
    });

5) Does not work:

    $(window).bind("load", function() {
        CSSDone();
    });

Believe me. Nothing works......

One workaround:

I load the css in the DOM and immidiately remove it again with jQuery. That way when adding the link to the head later it's fast enough.

回答1:

You need to insert a link node in the head and then attach onload event to that. In your code link is a String. See sample code below on how to implement what you want.

var link = document.createElement('link');
link.setAttribute("rel", "stylesheet");
link.setAttribute("type", "text/css");
link.onload = function(){ CSSDone(); }
link.setAttribute("href", 'https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css');
document.getElementsByTagName("head")[0].appendChild(link);

jsfiddle

回答2:

You can try this i believe.. include the CSSDone() code in $("head").append(link)'s callback

$(document).ready(function(){
$('.btn').on('click', function(){
link = "<link class='listcss' rel='stylesheet' href='/list.css'>";
        $("head").append(link, function(){
        if($(window).width()>640){
                $(".grid-item").css({"height":$(".grid-item").width()*0.2});
                $(".grid_item_img").css({"height":$(".grid-item").width()*0.2});
            console.log("a");
            }else{
                $(".grid-item").css({"height":$(".grid-item").width()*0.33});
                $(".grid_item_img").css({"height":$(".grid-item").width()*0.33});
            console.log("b");       
            }

        }); // append link

        }); // button click
}); // document ready

来源：https://stackoverflow.com/questions/35644072/dynamically-load-css-stylesheet-and-wait-for-it-to-load

标签

css

document-ready