如何让html输入域中只填写英文，不能填写中文

<script language=javascript>
var keylastuplength=0;
function onlyEng()  //禁止用户输入中文或中文符号
{
var thisval=document.getElementById('catalogCode').value;
 
  var cArr = thisval.match(/[^\x00-\xff]/ig);
        var lengthstr =thisval.length + (cArr == null ? 0 : cArr.length);
  if(thisval.length!=lengthstr){
  document.getElementById('catalogCode').value=document.getElementById('catalogCode').value.substring(0,keylastuplength);
  }else{
  keylastuplength = thisval.length;
  }
}
</script>
<s:textfield cssClass="form-control" 
onkeyup="onlyEng();" 
id="catalogCode" required="required" 
placeholder="栏目标识号 如（ceshilanmu）" 
name="catalogInfo.cataCode">
</s:textfield>