网络图片延迟加载实现代码 超越jquery控件

<script src="js/jquery.js" type="text/javascript"></script>

<script src="js/MinmyLazyload.js" type="text/javascript"></script>

<script type="text/javascript">$("img").lazyload(); </script>

<script type="text/javascript">$("img").lazyload({ placeholder: "images/blue-loading.gif", effect:"fadeIn" });
</script>

(function($) {
$.fn.lazyload = function(options) {
var settings = {
threshold: 0,
failurelimit: 0,
event: "scroll",
effect: "show",//默认效果为show
container: window
};
if (options) {
$.extend(settings, options);
}
var elements = this;
if ("scroll" == settings.event) {
$(settings.container).bind("scroll", function(event) {
var counter = 0;
elements.each(function() {
if ($.abovethetop(this, settings) ||
$.leftofbegin(this, settings)
) {
self.loaded = false;
}
else if (!$.belowthefold(this, settings) &&
!$.rightoffold(this, settings)) {
self.loaded = false;
$(this).trigger("appear");
}
else {
self.loaded = true;
if (counter++ > settings.failurelimit) {
return false;
}
}
});
var temp = $.grep(elements, function(element) {
return !element.loaded;
});
elements = $(temp);
});
}
/**三超控件--作品**/
this.each(function() {
var self = this;
if (settings.placeholder) {
$(self).attr("src", settings.placeholder);
}
$(self).one("appear", function() {
if (!this.loaded) {
$("<img />")
.bind("load", function() {
$(self)
.hide()
.attr("src", $(self).attr("original"))
[settings.effect](settings.effectspeed);
self.loaded = true;
})
.attr("src", $(self).attr("original"));
};
});
if ("scroll" != settings.event) {
$(self).bind(settings.event, function(event) {
if (!self.loaded) {
$(self).trigger("appear");
}
});
}
});
$(settings.container).trigger(settings.event);
return this;
};
$.belowthefold = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).height() + $(window).scrollTop();
} else {
var fold = $(settings.container).offset().top + $(settings.container).height();
}
return fold <= $(element).offset().top - settings.threshold;
};
$.rightoffold = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).width() + $(window).scrollLeft();
} else {
var fold = $(settings.container).offset().left + $(settings.container).width();
}
return fold <= $(element).offset().left - settings.threshold;
};
$.abovethetop = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).scrollTop();
} else {
var fold = $(settings.container).offset().top;
}
return fold >= $(element).offset().top + settings.threshold + $(element).height();
};
$.leftofbegin = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).scrollLeft();
} else {
var fold = $(settings.container).offset().left;
}
return fold >= $(element).offset().left + settings.threshold + $(element).width();
};
$.extend($.expr[':'], {
"below-the-fold": "$.belowthefold(a, {threshold : 0, container: window})",
"above-the-fold": "!$.belowthefold(a, {threshold : 0, container: window})",
"right-of-fold": "$.rightoffold(a, {threshold : 0, container: window})",
"left-of-fold": "!$.rightoffold(a, {threshold : 0, container: window})"
});
})(jQuery);
/**