使用F12进行监视
本身是一个linkbutton，可以看到绑定了一个JavaScript
<a id="gvStaticConnection_ctl02_fresh" href="javascript:__doPostBack(‘gvStaticConnection$ctl02$fresh‘,‘‘)">Refresh</a>
然后在element中搜索JavaScript，发现如下代码。
在form中嵌套了2个div，中间是一段JavaScript代码。
<div> <input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value=""> <input type="hidden" name="__EVENTARGUMENT" id="__EVENTARGUMENT" value=""> <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUJMzkwNjgzNzg1ZBgBBRJndlN0YXRpY0Nvbm5lY3Rpb24PPCsADAEIAgFkMpKk471Gv2kC36HGZDQi3IDHc+gD0MIZt2NfaV1jqgg="> </div>
<script type="text/javascript"> //<![CDATA[ var theForm = document.forms[‘form1‘]; if (!theForm) { theForm = document.form1; } function __doPostBack(eventTarget, eventArgument) { if (!theForm.onsubmit || (theForm.onsubmit() != false)) { theForm.__EVENTTARGET.value = eventTarget; theForm.__EVENTARGUMENT.value = eventArgument; theForm.submit(); } } //]]> </script>
<div> <input type="hidden" name="__VIEWSTATEGENERATOR" id="__VIEWSTATEGENERATOR" value="A00F45E7"> <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEdAAuNjij2g8HmJzHvpgbbF2UABG/bDdI74QPKSd1GbZA1p63BzPafSbjFZYr7YmO2hZLYOUOqiZmmlUGNRTBh5x9UeQJeCn5nS3Bfxy0+ElgI+9rHUHz/Y3DEd+XunHJ2rU6E4dAYu7eDiCYafdT3BS0Dr0sw6HJovU56ooP5DqFtdDuddnR7NwTASVzh66LqbcoTbXzLtoGNIRcsVOw3Kqtt1UYiKMifYW4rKipFYzjzs/AhN/5B3flrm+45Mi+1IzazoFp37V/4pb3o2NkeiLIB"> </div>
https://stackoverflow.com/questions/3591634/how-to-use-dopostback
simply said, it is used mainly by controls with AutoPostBack property
http://www.dotnetspider.com/resources/189-AutoPostBack-What-How-works.aspx
if you want to implement autopostback for your custom control, then you need to implement IPostBackDataHandler
原文：http://www.cnblogs.com/chucklu/p/7942074.html