function validate_required(field,alerttxt) {
	with (field) {
  		if (value==null||value=="") {
    		alert(alerttxt); return false;
  		} 
  	}
}

function validate_maxlength(field,thislen,alerttxt) {
	with (field) {
  		if (value.length > thislen) {
    		alert(alerttxt); return false;
  		} 
  	}
}

function validate_matchval(field1,field2,alerttxt) {
	if (field1.value!=field2.value) {
    	alert(alerttxt); return false;
  	}
}

function validate_chk_array(field,alerttxt){
	isChk = 0;
	for (i=0; i<field.length; i++){
		if (field[i].checked) {
			isChk  = 1;
		} 
	}	
	if (isChk == 0){
		alert(alerttxt); return false;
	}
}