jquery插件ScrollTo，jquery滚动到指定位置，为什么老外的js就这么牛逼呢？与我自己写起来的插件相差不是一两米啊
/**
* jQuery.ScrollTo
* Copyright (c) 2007-2008 Ariel Flesler - aflesler(at)gmail(dot)com | http://flesler.blogspot.com
* Dual licensed under MIT and GPL.
* Date: 9/11/2008
*
* @projectDescription Easy element scrolling using jQuery.
* http://flesler.blogspot.com/2007/10/jqueryscrollto.html
* Tested with jQuery 1.2.6. On FF 2/3, IE 6/7, Opera 9.2/5 and Safari 3. on Windows.
*
* @author Ariel Flesler
* @version 1.4
*
* @id jQuery.scrollTo
* @id jQuery.fn.scrollTo
* @param {String, Number, DOMElement, jQuery, Object} target Where to scroll the matched elements.
* The different options for target are:
* - A number position (will be applied to all axes).
* - A string position ('44', '100px', '+=90', etc ) will be applied to all axes
* - A jQuery/DOM element ( logically, child of the element to scroll )
* - A string selector, that will be relative to the element to scroll ( 'li:eq(2)', etc )
* - A hash { top:x, left:y }, x and y can be any kind of number/string like above.
* @param {Number} duration The OVERALL length of the animation, this argument can be the settings object instead.
* @param {Object,Function} settings Optional set of settings or the onAfter callback.
* @option {String} axis Which axis must be scrolled, use 'x', 'y', 'xy' or 'yx'.
* @option {Number} duration The OVERALL length of the animation.
* @option {String} easing The easing method for the animation.
* @option {Boolean} margin If true, the margin of the target element will be deducted from the final position.
* @option {Object, Number} offset Add/deduct from the end position. One number for both axes or { top:x, left:y }.
* @option {Object, Number} over Add/deduct the height/width multiplied by 'over', can be { top:x, left:y } when using both axes.
* @option {Boolean} queue If true, and both axis are given, the 2nd axis will only be animated after the first one ends.
* @option {Function} onAfter Function to be called after the scrolling ends.
* @option {Function} onAfterFirst If queuing is activated, this function will be called after the first scrolling ends.
* @return {jQuery} Returns the same jQuery object, for chaining.
*
* @desc Scroll to a fixed position
* @example $('div').scrollTo( 340 );
*
* @desc Scroll relatively to the actual position
* @example $('div').scrollTo( '+=340px', { axis:'y' } );
*
* @dec Scroll using a selector (relative to the scrolled element)
* @example $('div').scrollTo( 'p.paragraph:eq(2)', 500, { easing:'swing', queue:true, axis:'xy' } );
*
* @ Scroll to a DOM element (same for jQuery object)
* @example var second_child = document.getElementById('container').firstChild.nextSibling;
* $('#container').scrollTo( second_child, { duration:500, axis:'x', onAfter:function(){
* alert('scrolled!!');
* }});
*
* @desc Scroll on both axes, to different values
* @example $('div').scrollTo( { top: 300, left:'+=200' }, { axis:'xy', offset:-20 } );
*/
;(function( $ ){
var $scrollTo = $.scrollTo = function( target, duration, settings ){
$(window).scrollTo( target, duration, settings );
};
$scrollTo.defaults = {
axis:'y',
duration:1
};
// Returns the element that needs to be animated to scroll the window.
// Kept for backwards compatibility (specially for localScroll & serialScroll)
$scrollTo.window = function( scope ){
return $(window).scrollable();
};
// Hack, hack, hack... stay away!
// Returns the real elements to scroll (supports window/iframes, documents and regular nodes)
$.fn.scrollable = function(){
return this.map(function(){
// Just store it, we might need it
var win = this.parentWindow || this.defaultView,
// If it's a document, get its iframe or the window if it's THE document
elem = this.nodeName == '#document' ? win.frameElement || win : this,
// Get the corresponding document
doc = elem.contentDocument || (elem.contentWindow || elem).document,
isWin = elem.setInterval;
return elem.nodeName == 'IFRAME' || isWin && $.browser.safari ? doc.body
: isWin ? doc.documentElement
: this;
});
};
$.fn.scrollTo = function( target, duration, settings ){
if( typeof duration == 'object' ){
settings = duration;
duration = 0;
}
if( typeof settings == 'function' )
settings = { onAfter:settings };
settings = $.extend( {}, $scrollTo.defaults, settings );
// Speed is still recognized for backwards compatibility
duration = duration || settings.speed || settings.duration;
// Make sure the settings are given right
settings.queue = settings.queue && settings.axis.length > 1;
if( settings.queue )
// Let's keep the overall duration
duration /= 2;
settings.offset = both( settings.offset );
settings.over = both( settings.over );
return this.scrollable().each(function(){
var elem = this,
$elem = $(elem),
targ = target, toff, attr = {},
win = $elem.is('html,body');
switch( typeof targ ){
// A number will pass the regex
case 'number':
case 'string':
if( /^([+-]=)?\d+(px)?$/.test(targ) ){
targ = both( targ );
// We are done
break;
}
// Relative selector, no break!
targ = $(targ,this);
case 'object':
// DOMElement / jQuery
if( targ.is || targ.style )
// Get the real position of the target
toff = (targ = $(targ)).offset();
}
$.each( settings.axis.split(''), function( i, axis ){
var Pos = axis == 'x' ? 'Left' : 'Top',
pos = Pos.toLowerCase(),
key = 'scroll' + Pos,
old = elem[key],
Dim = axis == 'x' ? 'Width' : 'Height',
dim = Dim.toLowerCase();
if( toff ){// jQuery / DOMElement
attr[key] = toff[pos] + ( win ? 0 : old - $elem.offset()[pos] );
// If it's a dom element, reduce the margin
if( settings.margin ){
attr[key] -= parseInt(targ.css('margin'+Pos)) || 0;
attr[key] -= parseInt(targ.css('border'+Pos+'Width')) || 0;
}
attr[key] += settings.offset[pos] || 0;
if( settings.over[pos] )
// Scroll to a fraction of its width/height
attr[key] += targ[dim]() * settings.over[pos];
}else
attr[key] = targ[pos];
// Number or 'number'
if( /^\d+$/.test(attr[key]) )
// Check the limits
attr[key] = attr[key] <= 0 ? 0 : Math.min( attr[key], max(Dim) );
// Queueing axes
if( !i && settings.queue ){
// Don't waste time animating, if there's no need.
if( old != attr[key] )
// Intermediate animation
animate( settings.onAfterFirst );
// Don't animate this axis again in the next iteration.
delete attr[key];
}
});
animate( settings.onAfter );
function animate( callback ){
$elem.animate( attr, duration, settings.easing, callback && function(){
callback.call(this, target, settings);
});
};
function max( Dim ){
var attr ='scroll'+Dim,
doc = elem.ownerDocument;
return win
? Math.max( doc.documentElement[attr], doc.body[attr] )
: elem[attr];
};
}).end();
};
function both( val ){
return typeof val == 'object' ? val : { top:val, left:val };
};
})( jQuery );
