function isAlphaNumberKey(myfield, evt)
{
    myfield=document.getElementById(myfield.id).value
    var charCode = (evt.which) ? evt.which : event.keyCode
    var keychar = String.fromCharCode(charCode);

    if(!((charCode>47 && charCode<58) || (charCode >= 97 && charCode <= 122) || (charCode >= 65 && charCode <= 91) || (charCode==8))) return false;
    return true;
} 
  
function isNumberdotKey(myfield, evt)
{
    myfield=document.getElementById(myfield.id).value
    var charCode = (evt.which) ? evt.which : event.keyCode
    var keychar = String.fromCharCode(charCode);
    var sindex=myfield.indexOf(".");

    if(!((charCode>47 && charCode<58)||(charCode==46) || (charCode==8))) return false;

    if(sindex >= 0)
    {  
        if(charCode==46) return false;               
    }  
    return true;
}

function isNumberKey(myfield, evt)
{
    myfield=document.getElementById(myfield.id).value
    var charCode = (evt.which) ? evt.which : event.keyCode
    var keychar = String.fromCharCode(charCode);

    if(!((charCode>47 && charCode<58 || (charCode==8)))) return false;
    return true;
}    

function isAlpha(evt)
{ 
    var charCode = (evt.which) ? evt.which : event.keyCode          
    if(!((charCode >= 97 && charCode <= 122) || (charCode >= 65 && charCode <= 91) || (charCode==8) || (charCode==32) )) return false;
    return true;
}  

function doKeypress(control)
{
    maxLength = control.attributes["maxLength"].value;
    value = control.value;
     if(maxLength && value.length > maxLength-1)
     {
          event.returnValue = false;
          maxLength = parseInt(maxLength);
     }
}

function doBeforePaste(control)
{
    maxLength = control.attributes["maxLength"].value;
    if(maxLength)
     {
          event.returnValue = false;
     }
}

function doPaste(control)
{
    maxLength = control.attributes["maxLength"].value;
    value = control.value;
    if(maxLength)
    {
          event.returnValue = false;
          maxLength = parseInt(maxLength);
          var oTR = control.document.selection.createRange();
          var iInsertLength = maxLength - value.length + oTR.text.length;
          var sData = window.clipboardData.getData("Text").substr(0,iInsertLength);
          oTR.text = sData;
     }
}

function isDate(dateStr) 
{
    var datePat = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)(\d{4})$/;
    var matchArray = dateStr.match(datePat); // is the format ok?

    if (matchArray == null) 
    {
        alert("Please enter your date as dd/mm/yyyy. Your current selection reads: " + dateStr);
        return false;
    }

    day = matchArray[1]; // p@rse date into variables
    month = matchArray[3];
    year = matchArray[5];

    if (month < 1 || month > 12) 
    { // check month range
        alert("Month must be between 1 and 12.");
        return false;
    }

    if (day < 1 || day > 31) 
    {
        alert("Day must be between 1 and 31.");
        return false;
    }

    if ((month==4 || month==6 || month==9 || month==11) && day==31) 
    {
        alert("Month "+month+" doesn't have 31 days!");
        return false;
    }

    if (month == 2) 
    { // check for february 29th
        var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
        if (day > 29 || (day==29 && !isleap)) 
        {
            alert("February " + year + " doesn't have " + day + " days!");
            return false;
        }
    }
    return true; // date is valid
}