Firefox window.parent.location

Question

I've a Html page index.htm which has an iframe to page search.htm the search.htm has code like this

function executeSearch() {     
        window.parent.location = "/SearchResults.aspx?t=" + txt_Search.value;
    }

this code executed now from index.htm page and it works great on IE and Chrome, but not FireFox ... is there any work around ?? I tried window.parent.location.href, window.opener.location, window.parent.document.location ... but nothing of those worked.

after searching the web i found some one with similar prob he said that this is a security settings in Firefox ... is this true?? and if so is there any workaround ?