JS

//扩展mui.showLoading
(function($, window) {
    //显示加载框
    $.showLoading = function(message,type) {
        if ($.os.plus && type !== 'div') {
            $.plusReady(function() {
                plus.nativeUI.showWaiting(message);
            });
        } else {
            var html = '';
            html += '<i class="mui-spinner mui-spinner-white"></i>';
            html += '<p class="text">' + (message || "数据加载中") + '</p>';
            //遮罩层
            var mask=document.getElementsByClassName("mui-show-loading-mask");
            if(mask.length==0){
                mask = document.createElement('div');
                mask.classList.add("mui-show-loading-mask");
                document.body.appendChild(mask);
                mask.addEventListener("touchmove", function(e){e.stopPropagation();e.preventDefault();});
            }else{
                mask[0].classList.remove("mui-show-loading-mask-hidden");
            }
            //加载框
            var toast=document.getElementsByClassName("mui-show-loading");
            if(toast.length==0){
                toast = document.createElement('div');
                toast.classList.add("mui-show-loading");
                toast.classList.add('loading-visible');
                document.body.appendChild(toast);
                toast.innerHTML = html;
                toast.addEventListener("touchmove", function(e){e.stopPropagation();e.preventDefault();});
            }else{
                toast[0].innerHTML = html;
                toast[0].classList.add("loading-visible");
            }
        }
    };
    //隐藏加载框
    $.hideLoading = function(callback) {
        if ($.os.plus) {
            $.plusReady(function() {
                plus.nativeUI.closeWaiting();
            });
        }
        var mask=document.getElementsByClassName("mui-show-loading-mask");
        var toast=document.getElementsByClassName("mui-show-loading");
        if(mask.length>0){
            mask[0].classList.add("mui-show-loading-mask-hidden");
        }
        if(toast.length>0){
            toast[0].classList.remove("loading-visible");
            callback && callback();
        }
    }
})(mui, window);

CSS

/*----------------mui.showLoading-start---------------*/
.mui-show-loading {
    position: fixed;
    padding: 5px;
    width: 120px;
    min-height: 120px;
    top: 45%;
    left: 50%;
    margin-left: -60px;
    background: rgba(0, 0, 0, 0.6);
    text-align: center;
    border-radius: 5px;
    color: #FFFFFF;
    visibility: hidden;
    margin: 0;
    z-index: 2000;
    -webkit-transition-duration: .2s;
    transition-duration: .2s;
    opacity: 0;
    -webkit-transform: scale(0.9) translate(-50%, -50%);
    transform: scale(0.9) translate(-50%, -50%);
    -webkit-transform-origin: 0 0;
    transform-origin: 0 0;
}
.mui-show-loading.loading-visible {
    opacity: 1;
    visibility: visible;
    -webkit-transform: scale(1) translate(-50%, -50%);
    transform: scale(1) translate(-50%, -50%);
}
.mui-show-loading .mui-spinner{
    margin-top: 24px;
    width: 36px;
    height: 36px;
}
.mui-show-loading .text {
    line-height: 1.6;
    font-family: -apple-system-font,"Helvetica Neue",sans-serif;
    font-size: 14px;
    margin: 10px 0 0;
    color: #fff;
}
.mui-show-loading-mask {
    position: fixed;
    z-index: 1000;
    top: 0;
    right: 0;
    left: 0;
    bottom: 0;
}
.mui-show-loading-mask-hidden{
    display: none !important;
}
/*----------------mui.showLoading-end---------------*/

使用

mui.showLoading("正在加载..", "div");
mui.hideLoading();