function SadeceRakam(e,allowedchars){
	var key=e.charCode==undefined?e.keyCode:e.charCode;
	if((/^[0-9]+$/.test(String.fromCharCode(key)))||key==0||key==13||isPassKey(key,allowedchars)){
		return true;
		}else{
		return false;
		}
}
function isPassKey(key,allowedchars){if(allowedchars!=null){for(var i=0;i<allowedchars.length;i++){if(allowedchars[i]==String.fromCharCode(key))return true;}}return false;}
function SadeceRakamBlur(e,clear){var nesne=e.target?e.target:e.srcElement;var val=nesne.value;val=val.replace(/^\s+|\s+$/g,"");if(clear)val=val.replace(/\s{2,}/g," ");nesne.value=val;}


function on_focus(deger, val)
{
	if (document.getElementById(deger).value==val) { document.getElementById(deger).value	=''; }
}
function on_blur(deger,val)
{
	if (document.getElementById(deger).value=='') { document.getElementById(deger).value	=val;}
}
function gonder(lnk)
{
	if ((document.getElementById('gun').value=='GG') || (document.getElementById('ay').value=='AA') || (document.getElementById('yil').value=='YYYY')) 		
	{
		document.getElementById('msgdiv').innerHTML = '<BLINK><b style="color:#900"> Tarih Girilmedi! </b></BLINK>';
	}else{

		tarih = new Date();
		yil = tarih.getYear();
		if (yil < 1000){
			if (yil < 70){
			yil = 2000 + yil;
			}
			else yil = 1900 + yil;
		}
	
		ay = tarih.getMonth()+1;
		if (ay < 10){
			ay ='0' + ay;
		}
		
		gun = tarih.getDate();
		if (gun < 10){
			gun ='0' + gun;
		}		
		
		
		tarih1=(gun-document.getElementById('gun').value)+((ay-document.getElementById('ay').value)*30)+((yil-document.getElementById('yil').value)*365);
		//alert(tarih1);
		//alert(gun);
		//alert(ay);
		//alert(yil);
		//tarih2=(document.getElementById('gun').value)+(document.getElementById('ay').value*30)+(document.getElementById('yil').value*365);

		//alert((tarih1-tarih2)); 
		//alert(24*365);
		
		//if ((tarih1-tarih2)>=(24*365)) {
		//	alert("büyük");
		//} else {
		//	alert("küçük");
		//}
		if (document.getElementById('yil').value>1900) {
			document.getElementById('tardiv').style.visibility = 'hidden';
			document.getElementById('checkdiv').style.visibility = 'hidden';
			document.getElementById('grsbtndiv').style.visibility = 'hidden';
			if ((tarih1/365)>=24) {
				document.forms["form1"].action=lnk;
				document.forms["form1"].submit();
			}else{
				document.getElementById('msgdiv').innerHTML = '<BLINK><b style="color:#900"> 24 yaşından küçüksünüz! </b></BLINK>';	
			}
		}else{
			document.getElementById('msgdiv').innerHTML = '<BLINK><b style="color:#900"> Yanlış tarih girdiniz! </b></BLINK>';
			document.getElementById('yil').focus();
		}

			
	}
}

function On_KeyPress(val)
{
	var application = navigator.appName;
	if (application == 'Microsoft Internet Explorer'){ x=2;
	}else if (application == 'Netscape'){
	x=1;
		if (val=='gun') {
			if (form1.gun.value.length >= x) { 
				document.getElementById('ay').value='';
				document.getElementById('ay').focus();
				return true;
			}
		}else if (val=='ay') {
			if (form1.ay.value.length >= x) { 
				document.getElementById('yil').value='';
				document.getElementById('yil').focus();
				return true;
			}
	
		}
		return true;
	}
}

function On_changefocus(val)
{
	document.getElementById('msgdiv').innerHTML = '&nbsp;';
	var application = navigator.appName;
	if (application == 'Microsoft Internet Explorer'){ 
	x=2;
		if (val=='gun') {
			if (form1.gun.value.length >= x) { 
				document.getElementById('ay').value='';
				document.getElementById('ay').focus();
				return true;
			}
		}else if (val=='ay') {
			if (form1.ay.value.length >= x) { 
				document.getElementById('yil').value='';
				document.getElementById('yil').focus();
				return true;
			}
	
		}
		return true;
	}else if (application == 'Netscape'){ 
	x=1;
	}
}



<!-- input icin -->
<!-- <input type="text" id="txtInput" onkeypress="return SadeceRakam(event);" onblur="SadeceRakamBlur(event,false);" />-->

<!-- textarea icin -->
<!-- <textarea cols="50" rows="10" id="txtArea" onkeypress="return SadeceRakam(event,['-']);" onblur="SadeceRakamBlur(event,true);"> </textarea>-->