bug 4464: properly check if a subfield is populated if it is in a textarea

Subfields whose contents are longer than 100 characters are represented on the
bib form using a <textarea> instead of a text <input>.  The check on whether
at least one subfield for a mandatory field is populated wasn't not
checking for <textarea> subfields.

Signed-off-by: Galen Charlton <gmcharlt@gmail.com>

koha-tmpl/intranet-tmpl/prog/en/modules/cataloguing/addbiblio.tmpl

@@ -148,6 +148,14 @@ function AreMandatoriesNotOk(){
 					}
 	    		}
 	    	}
+
+	    	elemtextareas = elem.getElementsByTagName('textarea');
+	    	for(var j=0,len2=elemtextareas.length; j<len2; j++){
+                // this bit assumes that the only textareas in this context would be for subfields
+                if (elemtextareas[j].value) {
+                    isempty = false;
+                }
+            }
     	}else{
     		isempty = false;
     	}