<input id="txt1" type="text" />
//键盘事件
window.onload = function() {
var oTxt = document.getElementById('txt1');
oTxt.onkeydown = function(ev) {
var oEvent = ev || event;
//0 48
//9 57
//退格 8
if (oEvent.keyCode != 8 && (oEvent.keyCode < 48 || oEvent.keyCode > 57)) {
return false;
}
//return false;
};
}