Проверка на ввод данных

function checkNumber(e)
{
  var e = e || window.event;
  if(e.ctrlKey||e.altKey)return;
  var c = e.charCode || e.keyCode;
  return ((c > 47) && (c < 58));
}
document.getElementById('numcode').onkeypress=checkNumber;

document.getElementById('numcode').addEventListener('keypress', function(e){
    if(e.ctrlKey || e.altKey) return;
    var c = e.charCode || e.keyCode;
    return ((c > 47) && (c < 58));
}, false);

function addEvent(elem, type, handler){
  if(elem.addEventListener){
    elem.addEventListener(type, handler, false);
  } else {
    elem.attachEvent('on'+type, function(){ handler.call( elem ); });
  }
  return false;
}
 
function checkNumber(e){
    e = e || window.event;
    if(e.ctrlKey || e.altKey) return;
    var c = e.charCode || e.keyCode;
    return ((c > 47) && (c < 58));
}
addEvent(document.getElementById('numcode'), 'keypress', checkNumber);

function key(){
    if (event.charCode>=48 && event.charCode<=57 )
    document.form1.pass.value='';        
}

document.getElementById('numcode').addEventListener('keypress', function(e){
    if(e.ctrlKey || e.altKey) return;
    var c = e.charCode || e.keyCode;
    return ((c > 47) && (c < 58));
}, false);

document.getElementById('numcode').addEventListener('keypress', function(e){
    var re = /^[0-9]+$/,
        key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
    if (!re.test(key)) {
       event.preventDefault();
       return false;
    }
}, false);

function checkNumber(e){
    var re = /^[0-9]+$/,
        key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
    if (!re.test(key)) {
       event.preventDefault();
       return false;
    }
}
var inp = document.getElementById('numcode');
inp.addEventListener('paste', checkNumber, false);
inp.addEventListener('keypress', checkNumber, false);

function key(){
    if (event.charCode>=48 && event.charCode<=57 )
    event.preventDefault();  
}