Question

当文档已加载以检查选择框的值以及该框发生更改时，我想在初始化阶段进行一些测试并执行一些更改。这是我的操作方式，并且工作正常，但是我想知道是否有更简单的方法，因为我必须通过一个函数来执行它，并在启动时调用它，并且在按钮改变时也调用它。 / p>

// In case this is baseline, project or pre-sales, we will have different text to be selected

  function project_type_value_check() { 
    switch ($("#project_type option:selected").val()){
      case "Baseline":
        $('#revenue_text').text("MRC (k€)");
        $("#revenue").attr("placeholder", "MRC (k€)");
        break;
      case "Pre-sales":
        alert('presales');
        break;
      default:
        $('#revenue_text').text("Revenue (k€)");
        $("#revenue").attr("placeholder", "Revenue (k€)");
    } 
  }

  // This is when the page loads
  project_type_value_check();

  // This is when the select box changes
  $('#project_type').change(function() {
    project_type_value_check();
  });

Answer 1

我认为这更优雅

var vals = {"Baseline":"MRC (k€)","Pre-sales":"Presales"}
$(function() {
  $('#project_type').on("change",function() {
    var val = this.value || "Baseline"
    var show = vals[val]
    if (val=="Pre-sales") alert(show);
    else { 
      $('#revenue_text').text(show);
      $("#revenue").attr("placeholder", show);
    }  
  }).trigger("change");
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<select id="project_type">
  <option value="">Please select</option>
  <option value="Baseline">Baseline</option>
  <option value="Pre-sales">Pre-sales</option>  
</select><br/>
<span id="revenue_text"></span>
<input type="text" id="revenue" value=""/>

在初始化时和更改时检查选择框的值

1 个答案: