checkbox选中根据点击先后顺序依次显示

<SCRIPT LANGUAGE="JavaScript">
        var cache=[];

        var cbs=document.getElementsByTagName("INPUT");

        for (var i=0;i<cbs.length;++i ) {

                if(cbs[i].type!='checkbox')continue;

                cbs[i].onclick=function (){

                        if(this.checked)

                                cache.push(this.value)

                        else

                                for (var i=0;i<cache.length;++i )

                                        if(cache[i]==this.value)

                                                return cache.splice(i,1);

                };

        };

        function checkvalue(){        alert(cache)}

</SCRIPT>