未捕获的TypeError：无法读取未定义的属性“top”

我得到了一个错误，如“Uncaught TypeError：无法读取属性’顶部’未定义”…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 = 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

我刚改变了

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

至

 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

放

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

你会得到你的答案。