Ext.extend(MainPanel, Ext.TabPanel, {

    initEvents : function(){
        MainPanel.superclass.initEvents.call(this);
        this.body.on('click', this.onClick, this);
    },

    onClick: function(e, target){
        if(target = e.getTarget('a:not(.exi)', 3)){
            var cls = Ext.fly(target).getAttributeNS('ext', 'cls');
            e.stopEvent();
            if(cls){
                var member = Ext.fly(target).getAttributeNS('ext', 'member');
                this.loadClass(target.href, cls, member);
            }else if(target.className == 'inner-link'){
                this.getActiveTab().scrollToSection(target.href.split('#')[1]);
            }else{
                window.open(target.href);
            }
        }else if(target = e.getTarget('.micon', 2)){
            e.stopEvent();
            var tr = Ext.fly(target.parentNode);
            if(tr.hasClass('expandable')){
                tr.toggleClass('expanded');
            }
        }
    },

    loadClass : function(href, cls, member, text){
        var id = 'docs-' + cls;
        var tab = this.getComponent(id);
        if(tab){
     tab.getUpdater().update(href,true);
            this.setActiveTab(tab);
            if(member){
                tab.scrollToMember(member);
            }
        }else{
            var autoLoad = {url: href,scripts:true};
            if(member){
                autoLoad.callback = function(){
                    Ext.getCmp(id).scrollToMember(member);
                }
            }
            var p = this.add(new DocPanel({
                id: id,
                cclass : cls,
text : text,
                autoLoad: autoLoad,
                iconCls: Docs.icons[cls]
            }));
            this.setActiveTab(p);
        }
    },

doSearch : function(e){
var k = e.getKey();
if(!e.isSpecialKey()){
var text = e.target.value;
if(!text){
this.searchStore.baseParams.q = '';
this.searchStore.removeAll();
}else{
this.searchStore.baseParams.q = text;
this.searchStore.reload();
}
}
}
});

刚用extjs,很多地方都找不到答应,麻烦大大们了.
想问:
1.怎么通过javascript获取其它标签下的对象(或者DOM元素)
2.怎么通过javascript设置标签切换
3.怎么样添加一个formpanel(或者basicform),然后ajax提交结果
4.怎么样指定一个form表单提交的target是当前窗格(tabpanel)
谢谢各位,急用,如果有相关的好的学习资料也可以介绍一下