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_AN_Call_createelement("createElement", document, "article"); 
(function (){ 
if (!window.addEventListener) return ; 
var pending = false , prevVal = null ; 
function updateSoon(){ 
if (!pending) { 
pending = true ; 
_AN_Call_settimeout("setTimeout", window, update, 250); 
} 
} 
function update(){ 
pending = false ; 
var marks = _AN_Call_getelementsbytagname("getElementsByTagName", document.getElementById("nav"), "a"), found; 
for (var i = 0; 
i < _AN_Read_length("length", marks); ++i){ 
var mark = marks[i], m; 
if (_AN_Call_getattribute("getAttribute", mark, "data-default")) { 
if (found == null ) found = i; 
} 
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var ref = document.getElementById(m[1]); 
if (ref && ref.getBoundingClientRect().top < 50) found = i; 
} 
} 
if (found != null  && found != prevVal) { 
prevVal = found; 
var lis = _AN_Call_getelementsbytagname("getElementsByTagName", document.getElementById("nav"), "li"); 
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i < _AN_Read_length("length", lis); ++i)lis[i].className = ""; 
for (var i = 0; 
i < _AN_Read_length("length", marks); ++i){ 
if (found == i) { 
marks[i].className = "active"; 
for (var n = marks[i]; 
n; n = n.parentNode)if (n.nodeName == "LI") n.className = "active"; 
} 
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marks[i].className = ""; 
} 
} 
} 
} 
window.addEventListener("scroll", updateSoon); 
window.addEventListener("load", updateSoon); 
window.addEventListener("hashchange", function (){ 
_AN_Call_settimeout("setTimeout", window, function (){ 
var hash = _AN_Read_hash("hash", _AN_Read_location("location", document)), found = null , m; 
var marks = _AN_Call_getelementsbytagname("getElementsByTagName", document.getElementById("nav"), "a"); 
for (var i = 0; 
i < _AN_Read_length("length", marks); i++ )if ((m = _AN_Read_href("href", marks[i]).match(/(#.*)/)) && m[1] == hash) { 
found = i; 
break ; 
} 
if (found != null ) for (var i = 0; 
i < _AN_Read_length("length", marks); i++ )marks[i].className = i == found? "active": ""; 
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, 300); 
} 
); 
} 
)();