[JQuery] API

:first 


.prev()      


  
$(selector1).find(selector2);      


$(selector1).filter(selector2);  



$(selector).length 


$(selector).eq(i)  


$("p").insertBefore("#foo") = $("#foo").before("p")   

* Reference
- jQuery基础---filter()和find()
- Difference Between Filter() And Find() In JQuery