SP.SOD.executeFunc('sp.js', 'SP.ClientContext', retrieveListItemsInclude); //确保js文件加载,再执行方法
function retrieveListItemsInclude() {
var clientContext = new SP.ClientContext.get_current();
var oList = clientContext.get_web().get_lists().getByTitle('背景图片');
var camlQuery = new SP.CamlQuery();
camlQuery.set_viewXml('<View><RowLimit>100</RowLimit></View>');
this.collListItem = oList.getItems(camlQuery);

clientContext.load(collListItem, 'Include(ServerUrl)'); //ServerUrl的路径类似---/DocLib/123.jpg;
clientContext.executeQueryAsync(
Function.createDelegate(this, this.onQuerySucceeded),
Function.createDelegate(this, this.onQueryFailed)
);
}
//成功回调函数
function onQuerySucceeded(sender, args) {
this.BackgroundImg = [];
var listItemEnumerator = collListItem.getEnumerator();
while (listItemEnumerator.moveNext()) {
var oListItem = listItemEnumerator.get_current();
/**这里需要注意!对于某些属性有自带的获取方法,比如:get_id(),get_title();
*但对于大多数的属性都必须使用get_item("属性名")来获取值,
**/而且”属性名“要跟 Include("属性名")中的属性名保持大小写一致!!
this.BackgroundImg.push(oListItem.get_item("ServerUrl"));
}

if (this.BackgroundImg.length > 0) {
var index = Math.floor((Math.random() * this.BackgroundImg.length)); //随机数
$("#s4-workspace").css("background-image", "url(" + this.BackgroundImg[index] + ")");
}
}
//失败回调函数
function onQueryFailed(sender, args) {
alert('Request failed. ' + args.get_message() +
'\n' + args.get_stackTrace());
}


要查看列表字段的名称(Title)和对应的内部名称(InternalName),可以参考官方文档:


function retrieveAllListsAllFields(siteUrl) {     var clientContext = new SP.ClientContext(siteUrl);     var oWebsite = clientContext.get_web();     var collList = oWebsite.get_lists();      this.listInfoArray = clientContext.loadQuery(collList,          'Include(Title,Fields.Include(Title,InternalName))');      clientContext.executeQueryAsync(         Function.createDelegate(this, this.onQuerySucceeded),          Function.createDelegate(this, this._onQueryFailed)     ); }  function onQuerySucceeded() {     var listInfo = '';      for (var i = 0; i < this.listInfoArray.length; i++) {         var oList = this.listInfoArray[i];         var collField = oList.get_fields();         var fieldEnumerator = collField.getEnumerator();                      while (fieldEnumerator.moveNext()) {             var oField = fieldEnumerator.get_current();             var regEx = new RegExp('name', 'ig');                          if (regEx.test(oField.get_internalName())) {                 listInfo += '\nList: ' + oList.get_title() +                      '\n\tField Title: ' + oField.get_title() +                      '\n\tField Name: ' + oField.get_internalName();             }         }     }     alert(listInfo); }  function onQueryFailed(sender, args) {     alert('Request failed. ' + args.get_message() +          '\n' + args.get_stackTrace()); }


参考:https://msdn.microsoft.com/zh-cn/library/office/jj163201.aspx