1.先写一个遮罩层和动态图片

loading = {
    show: function () {
      var html = '<div class="loading_image aiabase parbase section" tabindex="-1"' +
        'style="overflow: hidden; position: fixed;top: 0;right: 0;bottom: 0;left: 0;min-width: 320px;z-index: 1050;outline: 0;background: rgba(0, 0, 0, 0.4);">' +
        '<div class="landing" style="height: 100%;display: flex;align-items: center;flex-direction: column;justify-content: center;">' +
        '<img src="src/img/moving-loading.gif" style="width: 30%;max-width: 150px;"/>' +
        '</div></div>';
      $('body').append(html);
      $('body').addClass('loading_body');
    },
    hide: function () {
      if ($('.loading_image')) {
        $('.loading_image').remove();
        $('body').removeClass('loading_body');
      }
    },
  }

2.加在ajax 中

function ajaxForSth(data, successCallback, errorCallback, optionToken) {
    if (!$('.loading_image').html()) {
        loading.show();
    }
    var showLoading = false; // 标志
    var options = {
        type: 'POST',
        dataType: 'json',
        data: data,
        headers: { 'Content-Type': 'application/json' },
        url: url,
        cache: false,
        headers: { Authorization: "Bearer " + optionToken },
    };
    $.ajax(options).done(function (data) {
        if (!showLoading) {
            ctx.loading.hide();
        }
        if (typeof (successCallback) == 'function') {
            successCallback(data);
        }
    }).fail(function (jqXHR, status, errorThrown) {
        if (!showLoading) {
            ctx.loading.hide();
        }
        if (jqXHR.status == 401 && typeof (errorCallbackFour) == 'function') {
            errorCallbackF(jqXHR, status, errorThrown);
        }
    });
}

就实现了。