我有以下代码:
// Core Zoom Logic, independent of event listeners.
$.zoom = function(target, source, img) {
var outerWidth,
outerHeight,
xRatio,
yRatio,
offset,
position = $(target).css('position');
// This part of code is omitted
return {
init: function() {
outerWidth = $(target).outerWidth();
outerHeight = $(target).outerHeight();
xRatio = (img.width - outerWidth) / $(source).outerWidth();
yRatio = (img.height - outerHeight) / $(source).outerHeight();
offset = $(source).offset();
},
move: function (e) {
var left = (e.pageX - offset.left),
top = (e.pageY - offset.top);
top = Math.max(Math.min(top, outerHeight), 0);
left = Math.max(Math.min(left, outerWidth), 0);
img.style.left = (left * -xRatio) + 'px';
img.style.top = (top * -yRatio) + 'px';
},
automove: function() {
// can I recall this?
}
};
};
我想要实现的是在automove()函数中添加以下效果:
$(img).animate({
top: newTop,
left: newLeft,
}, 1000, function() {
automove(); /* recall */
});
但是如何从它的身体再次呼叫automove?也许我应该完全改变$ .zoom函数中声明函数的方式?
答案 0 :(得分:1)
尝试
$.zoom = function(target, source, img) {
var outerWidth,
outerHeight,
xRatio,
yRatio,
offset,
position = $(target).css('position');
// This part of code is omitted
var fnInit = function() {
outerWidth = $(target).outerWidth();
outerHeight = $(target).outerHeight();
xRatio = (img.width - outerWidth) / $(source).outerWidth();
yRatio = (img.height - outerHeight) / $(source).outerHeight();
offset = $(source).offset();
};
var fnMove = function (e) {
var left = (e.pageX - offset.left),
top = (e.pageY - offset.top);
top = Math.max(Math.min(top, outerHeight), 0);
left = Math.max(Math.min(left, outerWidth), 0);
img.style.left = (left * -xRatio) + 'px';
img.style.top = (top * -yRatio) + 'px';
};
var fnAutomove = function() {
$(img).animate({
top: newTop,
left: newLeft,
}, 1000, function() {
fnAutomove(); /* recall */
});
}
return {
init: fnInit,
move: fnMove,
automove: fnAutomove
};
};
答案 1 :(得分:1)
如果你想从内部递归调用automove()
,传统方法就是使用arguments.callee。因此代码看起来像:
return {
/* ... */
automove: function() {
$(img).animate({
top: newTop,
left: newLeft,
}, 1000,
arguments.callee /* recall */
);
}
}
但在HTML5中,这已被弃用,在严格模式下实际上是非法的。相反,你可以简单地给函数命名:
return {
/* ... */
automove: function myAutomove () { // <-- give it a name
$(img).animate({
top: newTop,
left: newLeft,
}, 1000,
myAutomove /* recall */
);
}
}
命名函数表达式适用于所有新旧浏览器,并且更易于阅读。
请注意:
如果一个函数不需要参数,你可以简单地将引用作为回调传递给它,而不是将它包装在一个匿名函数中:
setTimeout(function(){ foo() },100); // <-- this is completely unnecessary
setTimeout(foo,100); // <-- just need to do this instead