Question

我收到了类似＆＃34; Uncaught TypeError：无法读取属性＆＃39; top＆＃39;未定义＆＃34; ...我不知道修复的方法!! ..任何人都可以告诉我答案!!! .. var divPos = $（theID）.offset（）。顶部;

var aChildren = $("nav li").children(); // find the a children of the list items
var aArray = []; // create the empty aArray
    for (var i=0; i < aChildren.length; i++) {    
        var aChild = aChildren[i];
        var ahref = $(aChild).attr('href');
        aArray.push(ahref);
    } // this for loop fills the aArray with attribute href values

    $(window).scroll(function(){
        var windowPos = $(window).scrollTop()+85; // get the offset of the window from the top of page
        var windowHeight = $(window).height(); // get the height of the window
        var docHeight = $(document).height();

        for (var i=0; i < aArray.length; i++) {
            var theID = aArray[i];



            var divPos = $(theID).offset().top;// get the offset of the div from the top of page.... error occured here!!!




            var divHeight = $(theID).height(); // get the height of the div in question
            if (windowPos >= divPos && windowPos < (divPos + divHeight)) {
                $("a[href='" + theID + "']").addClass("active");
            } else {
                $("a[href='" + theID + "']").removeClass("active");
            }
        }

        if(windowPos + windowHeight == docHeight) {
            if (!$("nav li:last-child a").hasClass("active")) {
                var navActiveCurrent = $(".active").attr("href");
                $("a[href='" + navActiveCurrent + "']").removeClass("active");
                $("nav li:last-child a").addClass("active");
            }
        }
    });

Answer 1

我刚刚改变了

var divPos = $(theID).offset().top;

到

var divPosid = $(theID);
    if (!divPosid.length) {
        return;
    }
    var divPos = divPosid.offset().top; // get the offset of the div from the top of page

Answer 2

把

console.log(theID);
var divPos = $(theID).offset().top;

你会得到答案。

未捕获的TypeError：无法读取未定义的属性“top”

2 个答案: