<html>
<hrad>
<script>
onload=function(){
document.getElementById("txt1").onkeydown=function(event){
var v=this.value;
if(event.keyCode > 47 && event.keyCode < 58){
var char=String.fromCharCode(event.keyCode);
this.value=v+char;
}else if(event.keyCode==8){
if(v){
this.value=v.substring(0,v.length-1);
}
}
}
}
</script>
</hrad>
<body>
<input readonly id="txt1">
</body>
</html>
这样写能防止很多种意外输入非数字的情况
<hrad>
<script>
onload=function(){
document.getElementById("txt1").onkeydown=function(event){
var v=this.value;
if(event.keyCode > 47 && event.keyCode < 58){
var char=String.fromCharCode(event.keyCode);
this.value=v+char;
}else if(event.keyCode==8){
if(v){
this.value=v.substring(0,v.length-1);
}
}
}
}
</script>
</hrad>
<body>
<input readonly id="txt1">
</body>
</html>
这样写能防止很多种意外输入非数字的情况