javascript 未捕获的类型错误：无法读取 null 的属性“包含”
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Uncaught TypeError: Cannot read property 'contains' of null
提问by Exotical
I'm currently working on a project, where I'm using the following slider in the overal site:
我目前正在处理一个项目，我在整个站点中使用以下滑块：
For the particular page I'm currently working on I'm also making use of Walter Zorns' Drag&Drop image library. (Link Here)
对于我目前正在处理的特定页面，我还使用了 Walter Zorns 的拖放图像库。（链接在这里）
Now when I start to make use of the SET_DHTMLfunction, which is required for using the D&D library, my slider starts throwing errors:
现在，当我开始使用SET_DHTML使用 D&D 库所需的函数时，我的滑块开始抛出错误：
Uncaught TypeError: Cannot read property 'contains' of null
Uncaught TypeError: Cannot read property 'contains' of null
The line number given, sends me to the following line:
给出的行号将我发送到以下行：
if($(itemsSpan[currNo]).css('bottom') == 0) {
if($(itemsSpan[currNo]).css('bottom') == 0) {
Which lies in the following piece of code:
这在下面的一段代码中：
s3Slider = function(id, vars) {
var element = this;
var timeOut = (vars.timeOut != undefined) ? vars.timeOut : 2000;
var current = null;
var timeOutFn = null;
var faderStat = true;
var mOver = false;
var items = $("#sliderContent .sliderTopstory");
var itemsSpan = $("#sliderContent .sliderTopstory span");
items.each(function(i) {
$(items[i]).mouseover(function() {
mOver = true;
});
$(items[i]).mouseout(function() {
mOver = false;
fadeElement(true);
});
});
var fadeElement = function(isMouseOut) {
var thisTimeOut = (isMouseOut) ? (timeOut/2) : timeOut;
thisTimeOut = (faderStat) ? 10 : thisTimeOut;
if(items.length > 0) {
timeOutFn = setTimeout(makeSlider, thisTimeOut);
} else {
console.log("Poof..");
}
}
var makeSlider = function() {
current = (current != null) ? current : items[(items.length-1)];
var currNo = jQuery.inArray(current, items) + 1
currNo = (currNo == items.length) ? 0 : (currNo - 1);
var newMargin = $(element).width() * currNo;
if(faderStat == true) {
if(!mOver) {
$(items[currNo]).fadeIn((timeOut/6), function() {
/* This line -> */if($(itemsSpan[currNo]).css('bottom') == 0) {
$(itemsSpan[currNo]).slideUp((timeOut/6), function( ) {
faderStat = false;
current = items[currNo];
if(!mOver) {
fadeElement(false);
}
});
} else {
$(itemsSpan[currNo]).slideDown((timeOut/6), function() {
faderStat = false;
current = items[currNo];
if(!mOver) {
fadeElement(false);
}
});
}
});
}
} else {
if(!mOver) {
if($(itemsSpan[currNo]).css('bottom') == 0) {
$(itemsSpan[currNo]).slideDown((timeOut/6), function() {
$(items[currNo]).fadeOut((timeOut/6), function() {
faderStat = true;
current = items[(currNo+1)];
if(!mOver) {
fadeElement(false);
}
});
});
} else {
$(itemsSpan[currNo]).slideUp((timeOut/6), function() {
$(items[currNo]).fadeOut((timeOut/6), function() {
faderStat = true;
current = items[(currNo+1)];
if(!mOver) {
fadeElement(false);
}
});
});
}
}
}
}
makeSlider();
};
Why is this error being thrown?
为什么会抛出这个错误？
Thanks.
谢谢。
采纳答案by Mike S.
I think your problem lies in these two lines:
我认为你的问题在于这两行：
var currNo = jQuery.inArray(current, items) + 1
currNo = (currNo == items.length) ? 0 : (currNo - 1);
If jQuery doesn't find the item in the array, it's going to send you a value of -1 (on the top line) which will then be changes to 0 because you added 1. Now, if currNo is 0 on the second line, it's going to change it back to -1, which will return you undefined. Maybe try and change it to do this instead:
如果 jQuery 没有在数组中找到该项目，它将向您发送一个 -1（在第一行）的值，然后由于您添加了 1，该值将更改为 0。现在，如果第二行的 currNo 为 0 ，它将把它改回 -1，这将返回 undefined。也许尝试更改它以执行此操作：
var currNo = jQuery.inArray(current, items);
if (currNo === items.length - 1) {
currNo = 0;
}
I'm not positive this is the problem, but I can see this becoming an issue if it's not the problem you're currently having.
我不确定这是问题所在，但如果这不是您目前遇到的问题，我可以看到这会成为一个问题。
