<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'
src='http://code.jquery.com/jquery-2.0.2.js'></script>
<style type='text/css'>
.fadein {
display: none;
}
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$(window).load(function(){
$('.fadein').fadeIn(2500);
});
</script>
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<body>
<img src="http://www.w3cschool.cn/style/download.png" class="fadein" />
</body>
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