/****************************************************************************************
  Function checkField(fieldName): check syntax of input text field, e.g. Registration
  form.
****************************************************************************************/
function checkField(fieldName) {
 var CurrentDocument=document.forms[0];
 var result="";

 // Check sintax of field value
for (i1=0; i1<CurrentDocument.elements[fieldName].value.length; i1++) 
{
	  if (	CurrentDocument.elements[fieldName].value.charCodeAt(i1)==34 ||		     // Char "
		     CurrentDocument.elements[fieldName].value.charCodeAt(i1)==39 ||		     // Char '
      		CurrentDocument.elements[fieldName].value.charCodeAt(i1)==58 ||		     // Char :
		     CurrentDocument.elements[fieldName].value.charCodeAt(i1)==59 ||		     // Char ;
		     CurrentDocument.elements[fieldName].value.charCodeAt(i1)==92 ||		     // Char \
		     CurrentDocument.elements[fieldName].value.charCodeAt(i1)==96 ||		     // Char `
		     CurrentDocument.elements[fieldName].value.charCodeAt(i1)==124) 			// Char |
		{
			alert("Please don't use the following chars: \" ' \ | : ; ` ");
		     result = "";
		     break;
		} else if ((CurrentDocument.elements[fieldName].value.charCodeAt(i1)!=32) || (result!="")) {
		     // Create new field value without left empty spaces (by appending each char).
		     result = result + CurrentDocument.elements[fieldName].value.charAt(i1);
		}
 }

 // Field value is OK
 return result;
}