输入框失去焦点只能输入数字

<h2 style="margin-left:80px;display:inline;margin:">分值结果</h2><button  type="button" class="btn btn-danger" id="additem">添加一个分值范围</button>
<div id="cc">
	<div id="first">
		<div class="form-group">
			<label class="col-sm-3 control-label no-padding-right" for="form-input-readonly"> 得分范围</label>
			<div class="col-sm-9">
				<input type="text"  name="scopeA[]"  class="col-xs-1 col-sm-1" placeholder="0" onblur="checkok(this)">
				<input type="text"  name="scopeB[]"  class="col-xs-1 col-sm-1" placeholder="30" onblur="checkok(this)" >
			</div>
		</div>
		<div class="form-group">
			<label class="col-sm-3 control-label no-padding-right" for="form-input-readonly"> 结果</label>
			<div class="col-sm-9">
				<textarea name="result[]" style="width:500px;height:100px">您好,你有轻度抑郁</textarea>
			</div>
		</div>
	</div>
</div>
<script>
$(function(){
	var html=$("#first").html();
	$("#additem").click(function(){
		$("#cc").append(html);
	});
})
function checkok(obj){
	obj.value=obj.value.replace(/[^0-9]+/,'')
	if (obj.value=='') {
		alert('请输入数值');
		obj.value=0;//设默认值
		obj.focus();
	}
}
</script>

//另外一种方法,onblur不好用
<input type='text' onkeyup="(this.v=function(){this.value=this.value.replace(/[^0-9-]+/,'');}).call(this)" onblur="this.v();" />