Get the JavaScript variable in formsubmit

I have an issue with screen scraping. In the page the links are available as follows,

<a id="linkbuttonAlphaA" href="javascript:__doPostBack('linkbuttonAlphaA','')">A</a>
<a id="linkbuttonAlphaB" href="javascript:__doPostBack('linkbuttonAlphaB','')">B</a>

<a id ="linkbuttonAlphaC"ref="javascript:__doPostBack('linkbut开发者_高级运维tonAlphaC','')">C</a>

The __doPostBack function contains this

function __doPostBack(eventTarget, eventArgument) {
if (!theForm.onsubmit || (theForm.onsubmit() != false)) {
    theForm.__EVENTTARGET.value = eventTarget;
    theForm.__EVENTARGUMENT.value = eventArgument;
    theForm.submit();
}

In this is it possible to set eventTarget and eventArgument manually? That means by passing that values in the URL and call the __doPostBack function?

If you want to hard code the values why not use two hidden fields and set their values and post the page. It would not be displayed on the url.

If you look at this link http://www.xefteri.com/articles/show.cfm?id=18, it would make things clear to you.