JavaScript实现的ArrayList类[原创][3]

    }

    this.contains = function(elem) {
        return this.indexof(elem) >= 0;
    }

    function ensurecapacity (mincapacity) {
        var oldcapacity = elementdata.length;
        if (mincapacity > oldcapacity) {
            var olddata = elementdata;
            var newcapacity = parseint( (oldcapacity * 3)/2 + 1 );
            if (newcapacity < mincapacity){
                newcapacity = mincapacity;
            }
            elementdata = new array(newcapacity);
            for( var i=0;i<oldcapacity;i++ ){
                elementdata[i] = olddata[i];
            }
        }
    }