lazyLoad = (
function
() {
var
map_element = {};
var
element_obj = [];
var
download_count = 0;
var
last_offset = -1;
var
doc_body;
var
doc_element;
var
lazy_load_tag;
function
initVar(tags) {
doc_body = document.body;
doc_element = document.compatMode ==
'BackCompat'
? doc_body : document.documentElement;
lazy_load_tag = tags || [
"img"
,
"iframe"
];
};
function
initElementMap() {
var
all_element = [];
for
(
var
i = 0,
len = lazy_load_tag.length; i < len; i++) {
var
el = document.getElementsByTagName(lazy_load_tag[i]);
for
(
var
j = 0,
len2 = el.length; j < len2; j++) {
if
(
typeof
(el[j]) ==
"object"
&& el[j].getAttribute(
"lazy_src"
)) {
element_obj.push(all_element[key]);
}
}
}
for
(
var
i = 0,
len = element_obj.length; i < len; i++) {
var
o_img = element_obj[i];
var
t_index = getAbsoluteTop(o_img);
if
(map_element[t_index]) {
map_element[t_index].push(i);
}
else
{
var
t_array = [];
t_array[0] = i;
map_element[t_index] = t_array;
download_count++;
}
}
};
function
initDownloadListen() {
if
(!download_count)
return
;
var
offset = (window.MessageEvent && !document.getBoxObjectFor) ? doc_body.scrollTop : doc_element.scrollTop;
var
visio_offset = offset + doc_element.clientHeight;
if
(last_offset == visio_offset) {
setTimeout(initDownloadListen, 200);
return
;
}
last_offset = visio_offset;
var
visio_height = doc_element.clientHeight;
var
img_show_height = visio_height + offset;
for
(
var
key
in
map_element) {
if
(img_show_height > key) {
var
t_o = map_element[key];
var
img_vl = t_o.length;
for
(
var
l = 0; l < img_vl; l++) {
element_obj[t_o[l]].src = element_obj[t_o[l]].getAttribute(
"lazy_src"
);
}
delete
map_element[key];
download_count--;
}
}
setTimeout(initDownloadListen, 200);
};
function
getAbsoluteTop(element) {
if
(arguments.length != 1 || element ==
null
) {
return
null
;
}
var
offsetTop = element.offsetTop;
while
(element = element.offsetParent) {
offsetTop += element.offsetTop;
}
return
offsetTop;
}
function
init(tags) {
initVar(tags);
initElementMap();
initDownloadListen();
};
return
{
init: init
}
})();
