Working with WebForm_DoPostBackWithOptions When Cleaning a Website

Question

I am trying to clear an aspx site displaying a list of search results using selenium; when the script button "clicks" on the button, a warning appears - I tried to press the "alert" button to go to the next page with EC.alert_is_present, but an error occurred ValueError: No JSON object could be decoded.

Having looked at the code of the button itself, using the 'inspect element shows:

<a onclick="WaitPlease('_ctl0_btnDownloadWordDocs');
if (ConfirmWordDocDownload()==false) return false;"

id="_ctl0_btnDownloadWordDocs" class="ButtonsMedium" href='javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions("_ctl0:btnDownloadWordDocs", "", true, "", "",false, true)) onclicksaved="function onclick(event){ WaitPlease('_ctl0_btnDownloadWordDocs');

if(ConfirmWordDocDownload()==false) return false;}">...</a>

I think this has something to do with WebForm_DoPostBackWithOptionsright after href, but googling did not give me any reference to this situation.

Thanks.