我真的不是JS，你能告诉我这段代码有什么问题吗？我试图添加这个但是出现错误“第74行出错，第3行：解析错误。”）'预期'。我真的不知道要修理什么。
<script id="gtm-scroll-tracking" type="text/javascript">
; (function (document, window, config) {
// Browser dependencies, script fails silently
if (!document.querySelector || !document.body.getBoundingClientRect) {
return false;
}
// Get our dataLayer ready, in case we're not in GTM or we've got a special name
var dataLayerName = config.dataLayerName || 'dataLayer';
var dataLayer = window[dataLayerName] || (window[dataLayerName] = []);
var cache = {};
// Initialize our distances, for later
config.distances = config.distances || {};
checkDepth();
addEvent(window, 'scroll', throttle(checkDepth, 500));
function getMarks(_docHeight, _offset) {
var marks = {};
var percents = [];
var pixels = []
if (config.distances.percentages) {
if (config.distances.percentages.each) {
percents = percents.concat(config.distances.percentages.each);
}
if (config.distances.percentages.every) {
var _every = every_(config.distances.percentages.every, 100);
percents = percents.concat(_every);
}
}
if (config.distances.pixels) {
if (config.distances.pixels.each) {
pixels = pixels.concat(config.distances.pixels.each);
}
if (config.distances.pixels.every) {
var _every = every_(config.distances.pixels.every, _docHeight);
pixels = pixels.concat(_every);
}
}
marks = addMarks_(marks, percents, '%', _docHeight, _offset);
marks = addMarks_(marks, pixels, 'px', _docHeight, _offset);
return marks;
}
function addMarks_(marks, points, symbol, _docHeight, _offset) {
var i;
for (i = 0; i < points.length; i++) {
var _point = parseInt(points[i], 10);
var height = symbol !== '%' ? _point + _offset : _docHeight *
(_point / 100) + _offset;
var mark = _point + symbol;
if (height <= _docHeight + _offset) { marks[mark] = height; }
}
return marks;
}
function every_(n, total) {
var n = parseInt(n, 10);
var _num = total / n;
var arr = [];
for (i = 1; i < _num + 1; i++) { arr.push(i * n); }
return arr;
}
function checkDepth() {
var _bottom = parseBorder_(config.bottom);
var _top = parseBorder_(config.top);
var height = docHeight(_bottom, _top);
var marks = getMarks(height, (_top || 0));
var _curr = currentPosition();
for (key in marks) {
if (_curr > marks[key] && !cache[key]) {
cache[key] = true;
fireAnalyticsEvent(key);
}
}
}
function fireAnalyticsEvent(distance) {
dataLayer.push({
'event': 'scrollTracking',
'attributes': { 'distance': distance }
});
}
}
function parseBorder_(border) {
if (typeof border === 'Number' || parseInt(border, 10)) {
return parseInt(border, 10);
}
try {
// If we have an element or a query selector, poll getBoundingClientRect
var el = border.nodeType && border.nodeType === 1 ? border :
document.querySelector(border);
var docTop = document.body.getBoundingClientRect().top;
var _elTop = Math.floor(el.getBoundingClientRect().top - docTop);
return _elTop;
} catch (e) { return void (0); }
}
// Adapted from
https://developer.mozilla.org/en-US/docs/Web/API/Window/scrollY
function currentPosition() {
var supportPageOffset = window.pageXOffset !== undefined;
var isCSS1Compat = ((document.compatMode || "") === "CSS1Compat");
var currScrollTop = supportPageOffset ?
window.pageYOffset :
isCSS1Compat ?
document.documentElement.scrollTop :
document.body.scrollTop;
return parseInt(currScrollTop, 10) + parseInt(viewportHeight(), 10);
}
function viewportHeight() {
var elem = (document.compatMode === "CSS1Compat") ?
document.documentElement :
document.body;
return elem.clientHeight;
}
function docHeight(_bottom, _top) {
var body = document.body;
var html = document.documentElement;
var height = Math.max(body.scrollHeight, body.offsetHeight,
html.clientHeight, html.scrollHeight, html.offsetHeight);
if (_top) { height = height - _top; }
if (_bottom) { height = _bottom - _top; }
return height - 5;
}
/*
* Throttle function borrowed from:
* Underscore.js 1.5.2
* http://underscorejs.org
*
(c) 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative
Reporters & Editors
* Underscore may be freely distributed under the MIT license.
*/
function throttle(func, wait) {
var context, args, result;
var timeout = null;
var previous = 0;
var later = function () {
previous = new Date;
timeout = null;
result = func.apply(context, args);
};
return function () {
var now = new Date;
if (!previous) previous = now;
var remaining = wait - (now - previous);
context = this;
args = arguments;
if (remaining <= 0) {
clearTimeout(timeout);
timeout = null;
previous = now;
result = func.apply(context, args);
} else if (!timeout) {
timeout = setTimeout(later, remaining);
}
return result;
};
}
// Cross-browser compliant event listener
function addEvent(el, evt, fn) {
if (el.addEventListener) { return el.addEventListener(evt, fn); }
if (el.attachEvent) {
return el.attachEvent('on' + evt, function (evt) {
// Call the event to ensure uniform 'this' handling, pass it event
fn.call(el, evt);
});
}
if (typeof el['on' + evt] === 'undefined' || el['on' + evt] === null) {
return el['on' + evt] = function (evt) {
// Call the event to ensure uniform 'this' handling, pass it event
fn.call(el, evt); \
}
}
}
})(document, window,
{
// False if you just use the default dataLayer variable, otherwise enter it here
'dataLayerName': false,
'distances': {
// Configure percentages of page you'd like to see if users scroll past
'percentages': {
'each': [10, 90],
'every': 25
},
// Configure for pixel measurements of page you'd like to see if users scroll past
'pixels': {
'each': [],
'every': null
}
},
// Accepts a number, DOM element, or query selector to determine the top of the scrolling area
'top': null,
// Accepts a number, DOM element, or query selector to determine the bottom of the scrolling area
'bottom': null,
});
</script>
在尝试预览（调试）时，该工具告诉我：
第74行出错，第3行：解析错误。 '）'预期