JavaScript asp.net Get the text in the current hyperlink_javascript skills

function openNo(sender)
{
var linkNo = sender.toString().split("'")[1].replace(/$/g,"_");
var strNo = document.getElementById(linkNo).innerText; //This is strNo
}
The link backend code is as follows:
my0000001
Among them:
sender=javascript:__doPostBack('ctl00$MainContent$BtnBaiyakuNo','')
linkNo = ctl00_MainContent_BtnBaiyakuNo
strNo = my0000001