Run this in any spreadsheet and it will list each of the sheets and, if a sheet is linked to a form, it will list the url, ID and Title of the linked form.
function LoopSheets4Forms(){
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheets = ss.getSheets();
var numSheets = sheets.length
if (numSheets > 1) {
for (i=0;i<numSheets;i++){
var sheetname = sheets[i].getName();
Logger.log("DEBUG:i="+i+", Sheet name: "+ sheetname);//DEBUG
var formURL = sheets[i].getFormUrl();
if(formURL != null){
// not null
Logger.log("DEBUG:Form url:"+formURL);//DEBUG
var form = FormApp.openByUrl(formURL);
Logger.log("DEBUG:Form title: "+form.getTitle());//DEBUG
var formId = form.getId();
Logger.log("DEBUG:Form id: "+ formId );//DEBUG
}
else
{
// is null
Logger.log("DEBUG: this sheet not linked to a form");//DEBUG
}
}
}
}