onselect and onselectstart

onselectstart比onselect 适用于更多的标记。
onselectstart Applies To:
A, ACRONYM, ADDRESS, AREA, B, BDO, BIG, BLOCKQUOTE, BODY, BUTTON, CAPTION, CENTER, CITE, CODE, CUSTOM, DD, DEL, DFN, DIR, DIV, DL, DT, EM, FIELDSET, FONT, FORM, hn, HR, I, IMG, INPUT type=button, INPUT type=checkbox, INPUT type=file, INPUT type=image, INPUT type=password, INPUT type=radio, INPUT type=reset, INPUT type=submit, INPUT type=text, KBD, LABEL, LI, LISTING, MAP, MARQUEE, MENU, nextID, NOBR, OBJECT, OL, OPTION, P, PLAINTEXT, PRE, Q, RT, RUBY, S, SAMP, SELECT, SMALL, SPAN, STRIKE, STRONG, SUB, SUP, TABLE, TBODY, TD, TEXTAREA, TFOOT, TH, THEAD, TR, TT, U, UL, VAR, XMP

onselect Applies To:
BODY, INPUT type=text, TEXTAREA

   onselect事件发生在mouseUp事件之后，而onselectstart 事件发生在mouseDown并mouseMove事件之后，因此onselect在HandleRelease()方法中调用过程中Fire的，而onselectstart事件得在HandleDrag()方法的调用过程中Fire，HandlePress()方法调用时还未检测到mouseMove事件，因此还不能确定是onselectstart事件。