点击了一个link button，查看后台调用

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

https://stackoverflow.com/questions/5376055/what-is-the-meaning-of-dopostback-function-and-when-is-it-used