<input value="" type="text" onkeyup="javascript:RepNumber(this)">

function RepNumber(obj) {  var reg = /^[/d]+$/g;  if (!reg.test(obj.value)) {    var txt = obj.value;    txt.replace(/[^0-9]+/,    function(char, index, val) { //匹配第一次非數字字符      obj.value = val.replace(//D/g, ""); //將非數字字符替換成""      var rtextRange = null;      if (obj.setSelectionRange) {        obj.setSelectionRange(index, index);      } else { //支持ie        rtextRange = obj.createTextRange();        rtextRange.moveStart('character', index);        rtextRange.collapse(true);        rtextRange.select();      }    })  }}

function chkNumber(eleText)    {       var value =eleText.value;       var len =value.length;       for(vari=0;i<len;i++)       {           if(value.charAt(i)>"9"|| value.charAt(i)<"0")           {              alert("含有非數字字符");              eleText.focus();              break;           }       }    }