yahoo.js

很棒的在线教学系统

        // dig into child objects the depth specifed. Default 3
        d = (L.isNumber(d)) ? d : 3;

        // arrays [1, 2, 3]
        if (L.isArray(o)) {
            s.push("[");
            for (i=0,len=o.length;i<len;i=i+1) {
                if (L.isObject(o[i])) {
                    s.push((d > 0) ? L.dump(o[i], d-1) : OBJ);
                } else {
                    s.push(o[i]);
                }
                s.push(COMMA);
            }
            if (s.length > 1) {
                s.pop();
            }
            s.push("]");
        // objects {k1 => v1, k2 => v2}
        } else {
            s.push("{");
            for (i in o) {
                if (L.hasOwnProperty(o, i)) {
                    s.push(i + ARROW);
                    if (L.isObject(o[i])) {
                        s.push((d > 0) ? L.dump(o[i], d-1) : OBJ);
                    } else {
                        s.push(o[i]);
                    }
                    s.push(COMMA);
                }
            }
            if (s.length > 1) {
                s.pop();
            }
            s.push("}");
        }

        return s.join("");
    },

    /**
     * Does variable substitution on a string. It scans through the string 
     * looking for expressions enclosed in { } braces. If an expression 
     * is found, it is used a key on the object.  If there is a space in
     * the key, the first word is used for the key and the rest is provided
     * to an optional function to be used to programatically determine the
     * value (the extra information might be used for this decision). If 
     * the value for the key in the object, or what is returned from the
     * function has a string value, number value, or object value, it is 
     * substituted for the bracket expression and it repeats.  If this
     * value is an object, it uses the Object's toString() if this has
     * been overridden, otherwise it does a shallow dump of the key/value
     * pairs.
     * @method substitute
     * @since 2.3.0
     * @param s {String} The string that will be modified.
     * @param o {Object} An object containing the replacement values
     * @param f {Function} An optional function that can be used to
     *                     process each match.  It receives the key,
     *                     value, and any extra metadata included with
     *                     the key inside of the braces.
     * @return {String} the substituted string
     */
    substitute: function (s, o, f) {
        var i, j, k, key, v, meta, saved=[], token, 
            DUMP='dump', SPACE=' ', LBRACE='{', RBRACE='}';


        for (;;) {
            i = s.lastIndexOf(LBRACE);
            if (i < 0) {
                break;
            }
            j = s.indexOf(RBRACE, i);
            if (i + 1 >= j) {
                break;
            }

            //Extract key and meta info 
            token = s.substring(i + 1, j);
            key = token;
            meta = null;
            k = key.indexOf(SPACE);
            if (k > -1) {
                meta = key.substring(k + 1);
                key = key.substring(0, k);
            }

            // lookup the value
            v = o[key];

            // if a substitution function was provided, execute it
            if (f) {
                v = f(key, v, meta);
            }

            if (L.isObject(v)) {
                if (L.isArray(v)) {
                    v = L.dump(v, parseInt(meta, 10));
                } else {
                    meta = meta || "";

                    // look for the keyword 'dump', if found force obj dump
                    var dump = meta.indexOf(DUMP);
                    if (dump > -1) {
                        meta = meta.substring(4);
                    }

                    // use the toString if it is not the Object toString 
                    // and the 'dump' meta info was not found
                    if (v.toString===Object.prototype.toString||dump>-1) {
                        v = L.dump(v, parseInt(meta, 10));
                    } else {
                        v = v.toString();
                    }
                }
            } else if (!L.isString(v) && !L.isNumber(v)) {
                // This {block} has no replace string. Save it for later.
                v = "~-" + saved.length + "-~";
                saved[saved.length] = token;

                // break;
            }

            s = s.substring(0, i) + v + s.substring(j + 1);


        }

        // restore saved {block}s
        for (i=saved.length-1; i>=0; i=i-1) {
            s = s.replace(new RegExp("~-" + i + "-~"), "{"  + saved[i] + "}", "g");
        }

        return s;
    },


    /**
     * Returns a string without any leading or trailing whitespace.  If 
     * the input is not a string, the input will be returned untouched.
     * @method trim
     * @since 2.3.0
     * @param s {string} the string to trim
     * @return {string} the trimmed string
     */
    trim: function(s){
        try {
            return s.replace(/^\s+|\s+$/g, "");
        } catch(e) {
            return s;
        }
    },

    /**
     * Returns a new object containing all of the properties of
     * all the supplied objects.  The properties from later objects
     * will overwrite those in earlier objects.
     * @method merge
     * @since 2.3.0
     * @param arguments {Object*} the objects to merge
     * @return the new merged object
     */
    merge: function() {
        var o={}, a=arguments;
        for (var i=0, l=a.length; i<l; i=i+1) {
            L.augmentObject(o, a[i], true);
        }
        return o;
    },

    /**
     * Executes the supplied function in the context of the supplied 
     * object 'when' milliseconds later.  Executes the function a 
     * single time unless periodic is set to true.
     * @method later
     * @since 2.4.0
     * @param when {int} the number of milliseconds to wait until the fn 
     * is executed
     * @param o the context object
     * @param fn {Function|String} the function to execute or the name of 
     * the method in the 'o' object to execute
     * @param data [Array] data that is provided to the function.  This accepts
     * either a single item or an array.  If an array is provided, the
     * function is executed with one parameter for each array item.  If
     * you need to pass a single array parameter, it needs to be wrapped in
     * an array [myarray]
     * @param periodic {boolean} if true, executes continuously at supplied 
     * interval until canceled
     * @return a timer object. Call the cancel() method on this object to 
     * stop the timer.
     */
    later: function(when, o, fn, data, periodic) {
        when = when || 0; 
        o = o || {};
        var m=fn, d=data, f, r;

        if (L.isString(fn)) {
            m = o[fn];
        }

        if (!m) {
            throw new TypeError("method undefined");
        }

        if (!L.isArray(d)) {
            d = [data];
        }

        f = function() {
            m.apply(o, d);
        };

        r = (periodic) ? setInterval(f, when) : setTimeout(f, when);

        return {
            interval: periodic,
            cancel: function() {
                if (this.interval) {
                    clearInterval(r);
                } else {
                    clearTimeout(r);
                }
            }
        };
    },
    
    /**
     * A convenience method for detecting a legitimate non-null value.
     * Returns false for null/undefined/NaN, true for other values, 
     * including 0/false/''
     * @method isValue
     * @since 2.3.0
     * @param o {any} the item to test
     * @return {boolean} true if it is not null/undefined/NaN || false
     */
    isValue: function(o) {
        // return (o || o === false || o === 0 || o === ''); // Infinity fails
return (L.isObject(o) || L.isString(o) || L.isNumber(o) || L.isBoolean(o));
    }

};

/**
 * Determines whether or not the property was added
 * to the object instance.  Returns false if the property is not present
 * in the object, or was inherited from the prototype.
 * This abstraction is provided to enable hasOwnProperty for Safari 1.3.x.
 * There is a discrepancy between YAHOO.lang.hasOwnProperty and
 * Object.prototype.hasOwnProperty when the property is a primitive added to
 * both the instance AND prototype with the same value:
 * <pre>
 * var A = function() {};
 * A.prototype.foo = 'foo';
 * var a = new A();
 * a.foo = 'foo';
 * alert(a.hasOwnProperty('foo')); // true
 * alert(YAHOO.lang.hasOwnProperty(a, 'foo')); // false when using fallback
 * </pre>
 * @method hasOwnProperty
 * @param {any} o The object being testing
 * @param prop {string} the name of the property to test
 * @return {boolean} the result
 */
L.hasOwnProperty = (Object.prototype.hasOwnProperty) ?
    function(o, prop) {
        return o && o.hasOwnProperty(prop);
    } : function(o, prop) {
        return !L.isUndefined(o[prop]) && 
                o.constructor.prototype[prop] !== o[prop];
    };

// new lang wins
OB.augmentObject(L, OB, true);

/*
 * An alias for <a href="YAHOO.lang.html">YAHOO.lang</a>
 * @class YAHOO.util.Lang
 */
YAHOO.util.Lang = L;
 
/**
 * Same as YAHOO.lang.augmentObject, except it only applies prototype 
 * properties.  This is an alias for augmentProto.
 * @see YAHOO.lang.augmentObject
 * @method augment
 * @static
 * @param {Function} r  the object to receive the augmentation
 * @param {Function} s  the object that supplies the properties to augment
 * @param {String*|boolean}  arguments zero or more properties methods to 
 *        augment the receiver with.  If none specified, everything
 *        in the supplier will be used unless it would
 *        overwrite an existing property in the receiver.  if true
 *        is specified as the third parameter, all properties will
 *        be applied and will overwrite an existing property in
 *        the receiver
 */
L.augment = L.augmentProto;

/**
 * An alias for <a href="YAHOO.lang.html#augment">YAHOO.lang.augment</a>
 * @for YAHOO
 * @method augment
 * @static
 * @param {Function} r  the object to receive the augmentation
 * @param {Function} s  the object that supplies the properties to augment
 * @param {String*}  arguments zero or more properties methods to 
 *        augment the receiver with.  If none specified, everything
 *        in the supplier will be used unless it would
 *        overwrite an existing property in the receiver
 */
YAHOO.augment = L.augmentProto;
       
/**
 * An alias for <a href="YAHOO.lang.html#extend">YAHOO.lang.extend</a>
 * @method extend
 * @static
 * @param {Function} subc   the object to modify
 * @param {Function} superc the object to inherit
 * @param {Object} overrides  additional properties/methods to add to the
 *        subclass prototype.  These will override the
 *        matching items obtained from the superclass if present.
 */
YAHOO.extend = L.extend;

})();
YAHOO.register("yahoo", YAHOO, {version: "2.6.0", build: "1321"});