实现jQuery中的animate 的background-color 属性的改变

/*!
 * jQuery Color Animations v@VERSION
 * https://github.com/jquery/jquery-color
 *
 * Copyright jQuery Foundation and other contributors
 * Released under the MIT license.
 * http://jquery.org/license
 *
 * Date: @DATE
 */

(function( root, factory ) {
    if ( typeof define === "function" && define.amd) {

        // AMD. Register as an anonymous module.
        define( [ "jquery" ], factory);
    } else if ( typeof exports === "object" ) {
        module.exports = factory( require( "jquery" ) );
    } else {
        factory( root.jQuery );
    }
})( this, function( jQuery, undefined ) {

    var stepHooks = "backgroundColor borderBottomColor borderLeftColor borderRightColor borderTopColor color columnRuleColor outlineColor textDecorationColor textEmphasisColor",

    // plusequals test for += 100 -= 100
    rplusequals = /^([\-+])=\s*(\d+\.?\d*)/,
    // a set of RE's that can match strings and generate color tuples.
    stringParsers = [{
            re: /rgba?\(\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,\s*(\d{1,3})\s*(?:,\s*(\d?(?:\.\d+)?)\s*)?\)/,
            parse: function( execResult ) {
                return [
                    execResult[ 1 ],
                    execResult[ 2 ],
                    execResult[ 3 ],
                    execResult[ 4 ]
                ];
            }
        }, {
            re: /rgba?\(\s*(\d+(?:\.\d+)?)\%\s*,\s*(\d+(?:\.\d+)?)\%\s*,\s*(\d+(?:\.\d+)?)\%\s*(?:,\s*(\d?(?:\.\d+)?)\s*)?\)/,
            parse: function( execResult ) {
                return [
                    execResult[ 1 ] * 2.55,
                    execResult[ 2 ] * 2.55,
                    execResult[ 3 ] * 2.55,
                    execResult[ 4 ]
                ];
            }
        }, {
            // this regex ignores A-F because it's compared against an already lowercased string
            re: /#([a-f0-9]{2})([a-f0-9]{2})([a-f0-9]{2})/,
            parse: function( execResult ) {
                return [
                    parseInt( execResult[ 1 ], 16 ),
                    parseInt( execResult[ 2 ], 16 ),
                    parseInt( execResult[ 3 ], 16 )
                ];
            }
        }, {
            // this regex ignores A-F because it's compared against an already lowercased string
            re: /#([a-f0-9])([a-f0-9])([a-f0-9])/,
            parse: function( execResult ) {
                return [
                    parseInt( execResult[ 1 ] + execResult[ 1 ], 16 ),
                    parseInt( execResult[ 2 ] + execResult[ 2 ], 16 ),
                    parseInt( execResult[ 3 ] + execResult[ 3 ], 16 )
                ];
            }
        }, {
            re: /hsla?\(\s*(\d+(?:\.\d+)?)\s*,\s*(\d+(?:\.\d+)?)\%\s*,\s*(\d+(?:\.\d+)?)\%\s*(?:,\s*(\d?(?:\.\d+)?)\s*)?\)/,
            space: "hsla",
            parse: function( execResult ) {
                return [
                    execResult[ 1 ],
                    execResult[ 2 ] / 100,
                    execResult[ 3 ] / 100,
                    execResult[ 4 ]
                ];
            }
        }],

    // jQuery.Color( )
    color = jQuery.Color = function( color, green, blue, alpha ) {
        return new jQuery.Color.fn.parse( color, green, blue, alpha );
    },
    spaces = {
        rgba: {
            props: {
                red: {
                    idx: 0,
                    type: "byte"
                },
                green: {
                    idx: 1,
                    type: "byte"
                },
                blue: {
                    idx: 2,
                    type: "byte"
                }
            }
        },

        hsla: {
            props: {
                hue: {
                    idx: 0,
                    type: "degrees"
                },
                saturation: {
                    idx: 1,
                    type: "percent"
                },
                lightness: {
                    idx: 2,
                    type: "percent"
                }
            }
        }
    },
    propTypes = {
        "byte": {
            floor: true,
            max: 255
        },
        "percent": {
            max: 1
        },
        "degrees": {
            mod: 360,
            floor: true
        }
    },
    support = color.support = {},

    // element for support tests
    supportElem = jQuery( "<p>" )[ 0 ],

    // colors = jQuery.Color.names
    colors,

    // local aliases of functions called often
    each = jQuery.each;

// determine rgba support immediately
supportElem.style.cssText = "background-color:rgba(1,1,1,.5)";
support.rgba = supportElem.style.backgroundColor.indexOf( "rgba" ) > -1;

// define cache name and alpha properties
// for rgba and hsla spaces
each( spaces, function( spaceName, space ) {
    space.cache = "_" + spaceName;
    space.props.alpha = {
        idx: 3,
        type: "percent",
        def: 1
    };
});

function clamp( value, prop, allowEmpty ) {
    var type = propTypes[ prop.type ] || {};

    if ( value == null ) {
        return (allowEmpty || !prop.def) ? null : prop.def;
    }

    // ~~ is an short way of doing floor for positive numbers
    value = type.floor ? ~~value : parseFloat( value );

    // IE will pass in empty strings as value for alpha,
    // which will hit this case
    if ( isNaN( value ) ) {
        return prop.def;
    }

    if ( type.mod ) {
        // we add mod before modding to make sure that negatives values
        // get converted properly: -10 -> 350
        return (value + type.mod) % type.mod;
    }

    // for now all property types without mod have min and max
    return 0 > value ? 0 : type.max < value ? type.max : value;
}

function stringParse( string ) {
    var inst = color(),
        rgba = inst._rgba = [];

    string = string.toLowerCase();

    each( stringParsers, function( i, parser ) {
        var parsed,
            match = parser.re.exec( string ),
            values = match && parser.parse( match ),
            spaceName = parser.space || "rgba";

        if ( values ) {
            parsed = inst[ spaceName ]( values );

            // if this was an rgba parse the assignment might happen twice
            // oh well....
            inst[ spaces[ spaceName ].cache ] = parsed[ spaces[ spaceName ].cache ];
            rgba = inst._rgba = parsed._rgba;

            // exit each( stringParsers ) here because we matched
            return false;
        }
    });

    // Found a stringParser that handled it
    if ( rgba.length ) {

        // if this came from a parsed string, force "transparent" when alpha is 0
        // chrome, (and maybe others) return "transparent" as rgba(0,0,0,0)
        if ( rgba.join() === "0,0,0,0" ) {
            jQuery.extend( rgba, colors.transparent );
        }
        return inst;
    }

    // named colors
    return colors[ string ];
}

color.fn = jQuery.extend( color.prototype, {
    parse: function( red, green, blue, alpha ) {
        if ( red === undefined ) {
            this._rgba = [ null, null, null, null ];
            return this;
        }
        if ( red.jquery || red.nodeType ) {
            red = jQuery( red ).css( green );
            green = undefined;
        }

        var inst = this,
            type = jQuery.type( red ),
            rgba = this._rgba = [];

        // more than 1 argument specified - assume ( red, green, blue, alpha )
        if ( green !== undefined ) {
            red = [ red, green, blue, alpha ];
            type = "array";
        }

        if ( type === "string" ) {
            return this.parse( stringParse( red ) || colors._default );
        }

        if ( type === "array" ) {
            each( spaces.rgba.props, function( key, prop ) {
                rgba[ prop.idx ] = clamp( red[ prop.idx ], prop );
            });
            return this;
        }

        if ( type === "object" ) {
            if ( red instanceof color ) {
                each( spaces, function( spaceName, space ) {
                    if ( red[ space.cache ] ) {
                        inst[ space.cache ] = red[ space.cache ].slice();
                    }
                });
            } else {
                each( spaces, function( spaceName, space ) {
                    var cache = space.cache;
                    each( space.props, function( key, prop ) {

                        // if the cache doesn't exist, and we know how to convert
                        if ( !inst[ cache ] && space.to ) {

                            // if the value was null, we don't need to copy it
                            // if the key was alpha, we don't need to copy it either
                            if ( key === "alpha" || red[ key ] == null ) {
                                return;
                            }
                            inst[ cache ] = space.to( inst._rgba );
                        }

                        // this is the only case where we allow nulls for ALL properties.
                        // call clamp with alwaysAllowEmpty
                        inst[ cache ][ prop.idx ] = clamp( red[ key ], prop, true );
                    });

                    // everything defined but alpha?
                    if ( inst[ cache ] && jQuery.inArray( null, inst[ cache ].slice( 0, 3 ) ) < 0 ) {
                        // use the default of 1
                        inst[ cache ][ 3 ] = 1;
                        if ( space.from ) {
                            inst._rgba = space.from( inst[ cache ] );
                        }
                    }
                });
            }
            return this;
        }
    },
    is: function( compare ) {
        var is = color( compare ),
            same = true,
            inst = this;

        each( spaces, function( _, space ) {
            var localCache,
                isCache = is[ space.cache ];
            if (isCache) {
                localCache = inst[ space.cache ] || space.to && space.to( inst._rgba ) || [];
                each( space.props, function( _, prop ) {
                    if ( isCache[ prop.idx ] != null ) {
                        same = ( isCache[ prop.idx ] === localCache[ prop.idx ] );
                        return same;
                    }
                });
            }
            return same;
        });
        return same;
    },
    _space: function() {
        var used = [],
            inst = this;
        each( spaces, function( spaceName, space ) {
            if ( inst[ space.cache ] ) {
                used.push( spaceName );
            }
        });
        return used.pop();
    },
    transition: function( other, distance ) {
        var end = color( other ),
            spaceName = end._space(),
            space = spaces[ spaceName ],
            startColor = this.alpha() === 0 ? color( "transparent" ) : this,
            start = startColor[ space.cache ] || space.to( startColor._rgba ),
            result = start.slice();

        end = end[ space.cache ];
        each( space.props, function( key, prop ) {
            var index = prop.idx,
                startValue = start[ index ],
                endValue = end[ index ],
                type = propTypes[ prop.type ] || {};

            // if null, don't override start value
            if ( endValue === null ) {
                return;
            }
            // if null - use end
            if ( startValue === null ) {
                result[ index ] = endValue;
            } else {
                if ( type.mod ) {
                    if ( endValue - startValue > type.mod / 2 ) {
                        startValue += type.mod;
                    } else if ( startValue - endValue > type.mod / 2 ) {
                        startValue -= type.mod;
                    }
                }
                result[ index ] = clamp( ( endValue - startValue ) * distance + startValue, prop );
            }
        });
        return this[ spaceName ]( result );
    },
    blend: function( opaque ) {
        // if we are already opaque - return ourself
        if ( this._rgba[ 3 ] === 1 ) {
            return this;
        }

        var rgb = this._rgba.slice(),
            a = rgb.pop(),
            blend = color( opaque )._rgba;

        return color( jQuery.map( rgb, function( v, i ) {
            return ( 1 - a ) * blend[ i ] + a * v;
        }));
    },
    toRgbaString: function() {
        var prefix = "rgba(",
            rgba = jQuery.map( this._rgba, function( v, i ) {
                return v == null ? ( i > 2 ? 1 : 0 ) : v;
            });

        if ( rgba[ 3 ] === 1 ) {
            rgba.pop();
            prefix = "rgb(";
        }

        return prefix + rgba.join() + ")";
    },
    toHslaString: function() {
        var prefix = "hsla(",
            hsla = jQuery.map( this.hsla(), function( v, i ) {
                if ( v == null ) {
                    v = i > 2 ? 1 : 0;
                }

                // catch 1 and 2
                if ( i && i < 3 ) {
                    v = Math.round( v * 100 ) + "%";
                }
                return v;
            });

        if ( hsla[ 3 ] === 1 ) {
            hsla.pop();
            prefix = "hsl(";
        }
        return prefix + hsla.join() + ")";
    },
    toHexString: function( includeAlpha ) {
        var rgba = this._rgba.slice(),
            alpha = rgba.pop();

        if ( includeAlpha ) {
            rgba.push( ~~( alpha * 255 ) );
        }

        return "#" + jQuery.map( rgba, function( v ) {

            // default to 0 when nulls exist
            v = ( v || 0 ).toString( 16 );
            return v.length === 1 ? "0" + v : v;
        }).join("");
    },
    toString: function() {
        return this._rgba[ 3 ] === 0 ? "transparent" : this.toRgbaString();
    }
});
color.fn.parse.prototype = color.fn;

// hsla conversions adapted from:
// https://code.google.com/p/maashaack/source/browse/packages/graphics/trunk/src/graphics/colors/HUE2RGB.as?r=5021

function hue2rgb( p, q, h ) {
    h = ( h + 1 ) % 1;
    if ( h * 6 < 1 ) {
        return p + (q - p) * h * 6;
    }
    if ( h * 2 < 1) {
        return q;
    }
    if ( h * 3 < 2 ) {
        return p + (q - p) * ((2/3) - h) * 6;
    }
    return p;
}

spaces.hsla.to = function ( rgba ) {
    if ( rgba[ 0 ] == null || rgba[ 1 ] == null || rgba[ 2 ] == null ) {
        return [ null, null, null, rgba[ 3 ] ];
    }
    var r = rgba[ 0 ] / 255,
        g = rgba[ 1 ] / 255,
        b = rgba[ 2 ] / 255,
        a = rgba[ 3 ],
        max = Math.max( r, g, b ),
        min = Math.min( r, g, b ),
        diff = max - min,
        add = max + min,
        l = add * 0.5,
        h, s;

    if ( min === max ) {
        h = 0;
    } else if ( r === max ) {
        h = ( 60 * ( g - b ) / diff ) + 360;
    } else if ( g === max ) {
        h = ( 60 * ( b - r ) / diff ) + 120;
    } else {
        h = ( 60 * ( r - g ) / diff ) + 240;
    }

    // chroma (diff) == 0 means greyscale which, by definition, saturation = 0%
    // otherwise, saturation is based on the ratio of chroma (diff) to lightness (add)
    if ( diff === 0 ) {
        s = 0;
    } else if ( l <= 0.5 ) {
        s = diff / add;
    } else {
        s = diff / ( 2 - add );
    }
    return [ Math.round(h) % 360, s, l, a == null ? 1 : a ];
};

spaces.hsla.from = function ( hsla ) {
    if ( hsla[ 0 ] == null || hsla[ 1 ] == null || hsla[ 2 ] == null ) {
        return [ null, null, null, hsla[ 3 ] ];
    }
    var h = hsla[ 0 ] / 360,
        s = hsla[ 1 ],
        l = hsla[ 2 ],
        a = hsla[ 3 ],
        q = l <= 0.5 ? l * ( 1 + s ) : l + s - l * s,
        p = 2 * l - q;

    return [
        Math.round( hue2rgb( p, q, h + ( 1 / 3 ) ) * 255 ),
        Math.round( hue2rgb( p, q, h ) * 255 ),
        Math.round( hue2rgb( p, q, h - ( 1 / 3 ) ) * 255 ),
        a
    ];
};


each( spaces, function( spaceName, space ) {
    var props = space.props,
        cache = space.cache,
        to = space.to,
        from = space.from;

    // makes rgba() and hsla()
    color.fn[ spaceName ] = function( value ) {

        // generate a cache for this space if it doesn't exist
        if ( to && !this[ cache ] ) {
            this[ cache ] = to( this._rgba );
        }
        if ( value === undefined ) {
            return this[ cache ].slice();
        }

        var ret,
            type = jQuery.type( value ),
            arr = ( type === "array" || type === "object" ) ? value : arguments,
            local = this[ cache ].slice();

        each( props, function( key, prop ) {
            var val = arr[ type === "object" ? key : prop.idx ];
            if ( val == null ) {
                val = local[ prop.idx ];
            }
            local[ prop.idx ] = clamp( val, prop );
        });

        if ( from ) {
            ret = color( from( local ) );
            ret[ cache ] = local;
            return ret;
        } else {
            return color( local );
        }
    };

    // makes red() green() blue() alpha() hue() saturation() lightness()
    each( props, function( key, prop ) {
        // alpha is included in more than one space
        if ( color.fn[ key ] ) {
            return;
        }
        color.fn[ key ] = function( value ) {
            var vtype = jQuery.type( value ),
                fn = ( key === "alpha" ? ( this._hsla ? "hsla" : "rgba" ) : spaceName ),
                local = this[ fn ](),
                cur = local[ prop.idx ],
                match;

            if ( vtype === "undefined" ) {
                return cur;
            }

            if ( vtype === "function" ) {
                value = value.call( this, cur );
                vtype = jQuery.type( value );
            }
            if ( value == null && prop.empty ) {
                return this;
            }
            if ( vtype === "string" ) {
                match = rplusequals.exec( value );
                if ( match ) {
                    value = cur + parseFloat( match[ 2 ] ) * ( match[ 1 ] === "+" ? 1 : -1 );
                }
            }
            local[ prop.idx ] = value;
            return this[ fn ]( local );
        };
    });
});

// add cssHook and .fx.step function for each named hook.
// accept a space separated string of properties
color.hook = function( hook ) {
    var hooks = hook.split( " " );
    each( hooks, function( i, hook ) {
        jQuery.cssHooks[ hook ] = {
            set: function( elem, value ) {
                var parsed, curElem,
                    backgroundColor = "";

                if ( value !== "transparent" && ( jQuery.type( value ) !== "string" || ( parsed = stringParse( value ) ) ) ) {
                    value = color( parsed || value );
                    if ( !support.rgba && value._rgba[ 3 ] !== 1 ) {
                        curElem = hook === "backgroundColor" ? elem.parentNode : elem;
                        while (
                            (backgroundColor === "" || backgroundColor === "transparent") &&
                            curElem && curElem.style
                        ) {
                            try {
                                backgroundColor = jQuery.css( curElem, "backgroundColor" );
                                curElem = curElem.parentNode;
                            } catch ( e ) {
                            }
                        }

                        value = value.blend( backgroundColor && backgroundColor !== "transparent" ?
                            backgroundColor :
                            "_default" );
                    }

                    value = value.toRgbaString();
                }
                try {
                    elem.style[ hook ] = value;
                } catch( e ) {
                    // wrapped to prevent IE from throwing errors on "invalid" values like 'auto' or 'inherit'
                }
            }
        };
        jQuery.fx.step[ hook ] = function( fx ) {
            if ( !fx.colorInit ) {
                fx.start = color( fx.elem, hook );
                fx.end = color( fx.end );
                fx.colorInit = true;
            }
            jQuery.cssHooks[ hook ].set( fx.elem, fx.start.transition( fx.end, fx.pos ) );
        };
    });

};

color.hook( stepHooks );

jQuery.cssHooks.borderColor = {
    expand: function( value ) {
        var expanded = {};

        each( [ "Top", "Right", "Bottom", "Left" ], function( i, part ) {
            expanded[ "border" + part + "Color" ] = value;
        });
        return expanded;
    }
};

// Basic color names only.
// Usage of any of the other color names requires adding yourself or including
// jquery.color.svg-names.js.
colors = jQuery.Color.names = {
    // 4.1. Basic color keywords
    aqua: "#00ffff",
    black: "#000000",
    blue: "#0000ff",
    fuchsia: "#ff00ff",
    gray: "#808080",
    green: "#008000",
    lime: "#00ff00",
    maroon: "#800000",
    navy: "#000080",
    olive: "#808000",
    purple: "#800080",
    red: "#ff0000",
    silver: "#c0c0c0",
    teal: "#008080",
    white: "#ffffff",
    yellow: "#ffff00",

    // 4.2.3. "transparent" color keyword
    transparent: [ null, null, null, 0 ],

    _default: "#ffffff"
};

});

                         引入 <script type="text/javascript" src="js/jquery.css.js"></script>  

 <script src="js/jquery.js" charset="utf-8"></script>

$( "#effect" ).animate({
                           backgroundColor: "#aa0000",
                         color: "#aa0000",
                         width: 500     
                           }, 1000 );