ajax返回参数中截取字符

String.substring(start,end)
实例：
function(i, item) {
$("#page").val(parseInt(parseInt(p)+1));
$(".jm_shop1").append('<div class="dz_Encyclopedias_list sjfx"><a href="URL/cases/id/'+item['sid']+'"><b><img src="/PUBLIC/Mobile/imgs/rexiao_08.png"/></b><em><h2>'+item['title']+'</h2><div class="baikee baikee1">'+item['cont']+'</div><span>'+item['addtime'].substring(0,10)+'</span></em></a></div>');
});