var r=document.getElementById('revert_');
if (this.value=='Revert')
{
/*
hide default input field(s) - q var
show revert to state as of datetime - r var
hide findreplace fr var
*/
q.style.display='none';
r.style.display='block';
fr.style.display='none';
/* cf refers to copy from field - not always present, e.g. date field */
if (typeof cf !== 'undefined')
{
// the variable is defined
cf.style.display='none';
}
let existingoptions = document.getElementById('displayexisting_');
if (existingoptions !== null)
{
existingoptions.style.display='none';
}
}
else
{
r.style.display='none';
}