Пример...
var a=[
{"id":"slide-img-1","client":"nature beauty","desc":"nature beauty photography"},
{"id":"slide-img-2","client":"nature beauty","desc":"add your description here"},
{"id":"slide-img-3","client":"nature beauty","desc":"add your description here"},
{"id":"slide-img-4","client":"nature beauty","desc":"add your description here"},
{"id":"slide-img-5","client":"nature beauty","desc":"add your description here"},
{"id":"slide-img-6","client":"nature beauty","desc":"add your description here"},
{"id":"slide-img-7","client":"nature beauty","desc":"add your description here"}
];
for (var i=0; i<a.length; i++) {
alert(a[i].id);
alert(a[i]['client']);
};