这是我正在处理的模块:
var FeatureRotator = (function($,global) {
var self = {},
currentFeature = 0,
images = [],
imagePrefix = "/public/images/features/",
timer = null,
totalImages = 0,
initialFeature,
interval,
blendSpeed,
element = null,
img1 = null,
img2 = null;
function setVisibleImage(iid) {
$("#img1").attr('src',images[iid].src).css('opacity',1);
$("#img2").css('opacity',0);
$(".active").removeClass("active");
$("#f"+iid).addClass("active");
}
function setCurrentImage(id) {
currentFeature = id;
setVisibleImage(id);
}
function doHoverIn(position) {
if (currentFeature === position) {
self.pause();
} else {
setCurrentImage(global.parseInt(position, 10));
self.pause();
}
}
function doHoverOut(position) {
self.unpause();
}
self.init = function(options,callback) {
var i = 0,
tempImg = null;
interval = options.interval || 5000;
blendSpeed = options.blendSpeed || 500;
element = options.element;
initialFeature = options.initialFeature || 0;
img1 = $("<img/>").attr('id','img1');
img2 = $("<img/>").attr('id','img2').css('opacity','0').css('margin-top',-options.height);
$(element).append(img1).append(img2);
totalImages = $(".feature").size();
for (i = 0;i < totalImages; i++) {
tempImg = new global.Image();
tempImg.src = imagePrefix +"feature_" + i + ".png";
images.push(tempImg);
$("#f"+i).css('background-image',
'url("'+imagePrefix+"feature_"+i+"_thumb.png"+'")')
.hover(doHoverIn($(this).attr('position'))
, doHoverOut($(this).attr('position'))
).attr('position',i);
}
setVisibleImage(initialFeature);
if (options.autoStart) {
self.start();
}
if (callback !== null) {
callback();
}
};
function updateImage() {
var active = $("#img1").css('opacity') === 1 ? "#img1" : "#img2";
var nextFeature = (currentFeature === totalImages-1 ? 0 : currentFeature+1);
if (active === "#img1") {
$("#img2").attr('src',images[nextFeature].src);
$("#img2").fadeTo(blendSpeed, 1);
$("#img1").fadeTo(blendSpeed, 0);
} else {
$("#img1").attr('src',images[nextFeature].src);
$("#img1").fadeTo(blendSpeed, 1);
$("#img2").fadeTo(blendSpeed, 0);
}
$("#f"+currentFeature).removeClass("active");
$("#f"+nextFeature).addClass("active");
currentFeature = nextFeature;
}
self.start = function() {
currentFeature = initialFeature;
setVisibleImage(currentFeature);
timer = global.setInterval(function(){
updateImage();
}, interval);
};
self.pause = function() {
global.clearTimeout(timer);
};
self.unpause = function() {
timer = global.setInterval(function(){
updateImage();
}, interval);
};
return self;
}(this.jQuery, this));
下面是它在页面上的使用方式:
<script type="text/javascript">
// ...
$(function() {
FeatureRotator.init({
interval:5000,
element:'#intro',
autoStart:true,
height:177,
blendSpeed:1000,
initialFeature:0
});
});
</script>
问题是,当从 init 方法调用 setVisibleImage 时,iid 的值为 NaN。我已经通过调试器并验证了调用 setVisibleImage 函数时“initialFeature”为 0,但遗憾的是,该值并未到达那里。
谁能帮我确定问题出在哪里?我已通过 JSLint 运行代码,并且返回时是干净的。
更新
好的,这是我更新后的代码,它现在可以工作了,除了淡入淡出不起作用,图像只是翻转到下一个并且不再平滑地淡入淡出:
var FeatureRotator = (function($,global) {
var self = {},
currentFeature = 0,
images = [],
imagePrefix = "/public/images/features/",
timer = null,
totalImages = 0,
initialFeature = 0,
interval,
blendSpeed;
function setVisibleImage(iid) {
$("#img1").attr('src',images[iid].src).css('opacity',1);
$("#img2").css('opacity',0);
$(".active").removeClass("active");
$("#f"+iid).addClass("active");
}
function setCurrentImage(id) {
currentFeature = id;
setVisibleImage(id);
}
function doHoverIn(obj) {
var position = global.parseInt(obj.target.attributes["position"].value,10);
if (currentFeature === position) {
self.pause();
} else {
setCurrentImage(global.parseInt(position, 10));
self.pause();
}
}
function doHoverOut() {
self.unpause();
}
self.init = function(options,callback) {
var i = 0,
tempImg = null,
element = null,
img1 = null,
img2 = null;
interval = options.interval || 5000;
blendSpeed = options.blendSpeed || 500;
element = options.element;
initialFeature = options.initialFeature || 0;
img1 = $("<img/>").attr('id','img1');
img2 = $("<img/>").attr('id','img2').css('opacity','0').css('margin-top',-options.height);
$(element).append(img1).append(img2);
totalImages = $(".feature").size();
for (i = 0;i < totalImages; i++) {
tempImg = new global.Image();
tempImg.src = imagePrefix +"feature_" + i + ".png";
images.push(tempImg);
$("#f"+i).css('background-image','url("'+imagePrefix+"feature_"+i+"_thumb.png"+'")')
.hover(doHoverIn, doHoverOut)
.attr('position',i);
}
setVisibleImage(initialFeature);
if (options.autoStart) {
self.start();
}
if (typeof callback === "function") {
callback();
}
};
function updateImage() {
var active = $("#img1").css('opacity') === 1 ? "#img1" : "#img2";
var nextFeature = (currentFeature === totalImages-1 ? 0 : currentFeature+1);
if (active === "#img1") {
$("#img2").attr('src',images[nextFeature].src);
$("#img2").fadeTo(blendSpeed, 1);
$("#img1").fadeTo(blendSpeed, 0);
} else {
$("#img1").attr('src',images[nextFeature].src);
$("#img1").fadeTo(blendSpeed, 1);
$("#img2").fadeTo(blendSpeed, 0);
}
$("#f"+currentFeature).removeClass("active");
$("#f"+nextFeature).addClass("active");
currentFeature = nextFeature;
}
self.start = function() {
currentFeature = initialFeature;
setVisibleImage(currentFeature);
timer = global.setInterval(function(){
updateImage();
}, interval);
};
self.stop = function() {
global.clearTimeout(timer);
};
self.pause = function() {
global.clearTimeout(timer);
};
self.unpause = function() {
timer = global.setInterval(function(){
updateImage();
}, interval);
};
return self;
}(this.jQuery, this));
最佳答案
因为你得到的是 NaN
,我猜它实际上是从这一行开始的:
.hover(doHoverIn($(this).attr('position'))
...这叫做:
setCurrentImage(global.parseInt(position, 10)); // note the parseInt()
...这叫做:
setVisibleImage(id);
因此传递给 parseInt
的 position
来自 $(this).attr('position')
,这可能是一个无法解析为数字的值,因此您得到 NaN
。
检查 for
语句 block 第一行中该属性的值。
for (i = 0;i < totalImages; i++) {
console.log( $(this).attr('position') ); // verify the value of position
// ...
关于javascript - 模块内部的简单函数调用,得到 NaN,是吗?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/4902430/