input 判断是否为正整数 并显示按钮或隐藏按钮

<form id="subForm" style="margin-top: 20px;" class="layui-form" action="<%=path%>/ap/ctrlApSetZetaParam?uid=${uid}" method="post">

    <div class="layui-form-item">
        <label class="layui-form-label">通信信道频点</label>
        <div class="layui-input-inline">
            <input onkeyup="this.value=this.value.replace(/[^0-9-]+.[^0-9-]+/);" oninput="OnInputMath (event)" onpropertychange="OnPropChangedMath (event)"
                   type="text" name="comFreq" style="width: 150px;" required lay-verify="required" placeholder="通信信道频点（1-15）" autocomplete="off" class="layui-input">
        </div>
    </div>

    <div class="layui-form-item" style="align-content: center">
        <div class="layui-input-block">
            <div id="subBTN" type="reset" class="layui-btn layui-btn-normal" onclick="submitForm()">确认</div>
        </div>
    </div>
</form>

function OnInputMath (event) {
    /*var reg=/^[1-9]\d*\.\d*|0\.\d*[1-9]\d*$/;*/
    var reg =  /^[1-9]+[0-9]*]*$/;
    if(event.target.value==""||reg.test(event.target.value)==true){
        if (event.target.value >= 0 && event.target.value <= 15) {
            document.getElementById("subBTN").style.display = '';
        } else {
            layer.msg("输入范围1~15");
            document.getElementById("subBTN").style.display = 'none';
        }
    } else {
        layer.msg("请输入数字 ");
        document.getElementById("subBTN").style.display = 'none';
    }
}
function OnPropChangedMath (event) {
    if (event.propertyName.toLowerCase () == "value") {
        /*var reg=/^[1-9]\d*\.\d*|0\.\d*[1-9]\d*$/;*/
        var reg =  /^[1-9]+[0-9]*]*$/;
        if(event.target.value==""||reg.test(event.target.value)==true){
            if (event.target.value >= 0 && event.target.value <= 15) {
                document.getElementById("subBTN").style.display = '';
            } else {
                layer.msg("输入范围1~15");
                document.getElementById("subBTN").style.display = 'none';
            }
        } else {
            layer.msg("请输入数字 ");
            document.getElementById("subBTN").style.display = 'none';
        }
    }
}