<ul class="easyui-tree" id="tt"></ul>

$(".next-menu:nth-child(1) a").click(function() {
var $IDstr = $(this).attr("id"),
$treeIDNum = parseInt($(this).attr("treeID")),
jsonURL = "json/" + $IDstr + ".json",
node;
addAttr2Tree(jsonURL)；
changeImgSrc($treeIDNum); 
});
});
function changeImgSrc(nodeID){
var node = $("#tt").tree('find', nodeID);
if(node){
$("#tt").tree('select', node.target);
}
if (node.attributes) {
$("#img-box").attr("src", node.attributes.url);
}
}
function addAttr2Tree(URL){
$("#tt").tree({
url: URL,
method: "get",
animate: true,
lines: true
});
}

$(".next-menu:nth-child(1) a").click(function() {
var $IDstr = $(this).attr("id"),
$treeIDNum = parseInt($(this).attr("treeID")),
jsonURL = "json/" + $IDstr + ".json",
node;
addAttr2Tree(jsonURL);
$("#tt").tree({
onLoadSuccess: function(){
changeImgSrc($treeIDNum);
}
});
});