javascript - 使用全局变量在循环内调用图像 onload

Question

变量menuitems 是一个键值对。键包含名称，值包含图像 url。这个想法是将以下 URL 存储在本地存储中。

本地存储变量为key_icon(key为图片名称)

下面是代码。假设有4个key，account, sms, group and history。

$.each(menuitems, function(key, value) {
    menu_icon_session_name = key+'_icon';
    var dataImage = localStorage.getItem(menu_icon_session_name);

    //The Div container to load the image
    div  = "<div class='ui-block-a'><div class='ui-bar' id='div_"+key+"' style='padding:5px'>" +
    "<img crossorigin='anonymous' width=150 height=150 id='btn_"+key+"' style='height: 100%; width:100%'>"
    "</div></div>";

    //Append the div container with empty image
    jQuery('#pg_home_content').append(div);

    //Based on the local storage load the image
    if(dataImage){
        console.log('loaded from session');
        bannerImg = document.getElementById('btn_'+key);
        bannerImg.src = dataImage;
        jQuery('#div_'+key).html(bannerImg);
    }else{
        console.log('loaded from url');
        bannerImage = document.getElementById('btn_'+key);
        bannerImage.setAttribute('crossOrigin', 'anonymous');

        bannerImage.src = value.menu_icon;
        bannerImage.onload = function () {
            imgData = getBase64Image(bannerImage);
            localStorage.setItem(menu_icon_session_name, imgData);
            console.log('stored '+menu_icon_session_name);
        }
    }
});

由于 onload 是异步 变量 menu_icon_session_name 被覆盖，所有图像都存储在最后一个变量 history_icon.

我想要做的就是将所有 4 个图像加载到单独的本地存储中并在以后使用它......

Answer 1

...stuff...

    bannerImage.src = value.menu_icon;
    bannerImage.attr('data-my-session-name', menu_icon_session_name);
    bannerImage.onload = function () {
        imgData = getBase64Image(this);
        localStorage.setItem($(this).attr('data-my-session-name'), imgData);            

...stuff...