根据 ${selectedcount} 显示不同的输出

Question

我希望预测公式 显示为：

如果 ${selectedcount} > 30

显示为${selectedcount} / 3 + 5

如果 ${selectedcount} < 30

显示为${selectedcount} / 3 - 5

P/S：不是计算，只是公式

<div id="demo" align="center"></div>

<script src="//code.jquery.com/jquery-1.12.0.min.js"></script>

<script type="text/javascript">

  var selectedcount = '';

function myFunction() {

    document.getElementById("demo").innerHTML = `

<table class="table table-striped table-dark" style="width:600px; float: right; margin-right: 330px;">

     <tr>

         <td style="text-align: center; color: #000000; text-align: left;">Current total number of students:</td>

         <td style="text-align: center; font-weight: bold; color: #000000; text-align: left;">${selectedcount} students</td>

     </tr>

<tr>

    <td style="text-align: center; color: #000000; text-align: left;">Prediction Formula:</td>

    <td style="text-align: center; color: #0000A0; text-align: left;">Number of students > 30 <br> <b>Average = number of students / 3 + 5</b></td>

  </tr>

  <tr>

    <td></td>

    <td style="text-align: center; color: #0000A0; text-align: left;">Number of students < 30 <br> <b>Average = number of students / 3 - 5</b></td>

  </tr>

</table>`

  }

$(document).ready(function(){

    $("#prg").change( function(){

      selectedcount = $('#prg option:selected').data('prgcount');

      if(selectedcount > 30){

        average = selectedcount / 3 + 5;

      } else{

        average = selectedcount / 3 - 5;

      }

    });

  });

</script>

目前，预测公式行未从当前学生总数中捕获 ${selectedcount}，如下所示：

屏幕截图

我已经删除了一些不相关的代码，希望对您有所帮助。请协助解决上述问题。谢谢你。

Answer 1

根据您的条件在渲染之前存储符号和分母。像这样的东西。function myFunction() {&nbsp; &nbsp;var predicDenom = parseInt(selectedcount) > 30 ? '3+5 : '3-5'; //Store the denominator based on number of students&nbsp; &nbsp;var predicSign = parseInt(selectedcount) > 30 ? '>' : '<'; // Also store the sign&nbsp; &nbsp; document.getElementById("demo").innerHTML = `<table class="table table-striped table-dark" style="width:600px; float: right; margin-right: 330px;">&nbsp; &nbsp; &nbsp;<tr>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<td style="text-align: center; color: #000000; text-align: left;">Current total number of students:</td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<td style="text-align: center; font-weight: bold; color: #000000; text-align: left;">${selectedcount} students</td>&nbsp; &nbsp; &nbsp;</tr><tr>&nbsp; &nbsp; <td style="text-align: center; color: #000000; text-align: left;">Prediction Formula:</td>&nbsp; &nbsp; <td style="text-align: center; color: #0000A0; text-align: left;">Number of students ${predicSign} 30 <br> <b>Average = number of students / ${predicDenom}</b></td>&nbsp; </tr></table>`&nbsp; }