如何输入身份证号码自动生成出生年月日

ftl代码：

<div class="form-group">

    <label class="col-sm-2 control-label"><span class="required">*span>证件类型：label>
    <div class="col-sm-4">
        <select id="zhengjtype" name="zhengjtype" class="form-control">
            <option value="1">身份证option>
        select>
    div>

    <label class="col-sm-2 control-label"><span class="required">*span>证件号码：label>
    <div class="col-sm-4">
        <input id="zhengjno" name="zhengjno" class="form-control" aria-required="true"
               aria-invalid="true" type="text" shfzhh="true" required  οnblur="ExtractionBirthday('zhengjno','driverbirthday')">
    div>
div>

js中的代码：

function ExtractionBirthday(oneText,twoText){

    var txtparm = document.getElementById(oneText).value;
    if(txtparm.length==18){
        var year = txtparm.substring(6,10);
        var month = txtparm.substring(10,12);
        var date=txtparm.substring(12,14);
        document.getElementById(twoText).value=year+"-"+month+"-"+date;
    }else if(txtparm.length==15){
        var year = txtparm.substring(6,8);
        var month = txtparm.substring(8,10);
        var date=txtparm.substring(10,12);
        document.getElementById(twoText).value=year+"-"+month+"-"+date;
    }
    else {
        alert("输入的身份证不正确！");

//如果通过测试，focus代码可以注释
        document.getElementById(oneText).focus();
        document.getElementById(oneText).value="";
    }

}