如何验证我输入文本框里的字符串都是由数字组成？？

1<script language="javascript">   
2.........   
3</script>

1<input name="t1" onblur="checknumber()"/>

怎么验证我输入文本框name里的的字符串都是数字组成？
---------------------------------------------------------------

function checknumber(){
if(/\D/.test(t1.value)) alert("必须是数字！");
}
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 1<script language="JavaScript">   
 2<!--   
 3  
 4function Check() {   
 5var Temp=Num.value.substring(0,Num.value.length-1);   
 6if(event.keyCode<48 ¦ ¦ event.keyCode>57)   
 7Num.value=Temp;   
 8  
 9}   
10\-->   
11</script>

1<input name="Num" onkeyup="Check()" onpaste="return false;" type="Text"/>

---------------------------------------------------------------

for( var i=0;i

 1<document.stationform.stationno.value.length;i++ ){="" ch="document.stationform.stationno.value.charAt(i);" if(!(ch="" var="">='0'&amp;&amp;ch&lt;='9')){   
 2alert("车站编号必须为数字!");   
 3document.stationform.stationno.focus();   
 4return false; }   
 5}   
 6\---------------------------------------------------------------   
 7  
 8function checknum(m)   
 9{   
10var flag = 0 ;   
11var n;   
12n = newform.fkm14.value;   
13if (isNaN(n)==true)   
14{   
15flag = flag + 1;   
16}   
17if (flag&gt;0)   
18{   
19alert("必须是数字！");   
20m.select();   
21}   
22}</document.stationform.stationno.value.length;i++>