Question

这是我的第一次编码，我试图在我的网站上创建一个功能，从下拉菜单中选择一个项目后，与该项目相对应的值将显示在我创建的输入框中。例如，如果我从下拉菜单中选择“苹果”，则值“ 1.2”和“ 4.00”将分别显示在“磅”和“成本”输入框中。

我已经为下拉菜单和输入框使用HTML和JS编写了代码，并且已经将与项目相对应的数据存储在csv文件中。现在，仅在输入框中显示值，因为我是用JS编写代码的。 HTML文件有什么方法可以从csv文件读取我的数据并在输入框中显示该数据？这是我到目前为止的内容。

<div id="cs-element">
  <label id="cs-element-label">Elements</label>
</div>

<select onChange="dropdownTip(this.value)" name="search_type" style="margin-right:10px; margin-top:2px;">
 <option selected="selected">Choose Element</option>
 <option>Methane</option>
 <option>Ethane</option>
 <option>Propane</option>
 <option>n-Butane</option>
</select>

<div id="result"></div>

<script type="text/javascript">
 function dropdownTip(value){
   console.log(value);
    document.getElementById("myText").value="190.6";
    document.getElementById("myText1").value="45.99";
    document.getElementById("myText2").value="0.012";
 }
</script>

<div id="cs-tc" class="col-sm-4 text-center">
  <label id="cs-tc-label" class="control-label">Critical Temperature (K)</label>
 <input type="text" id="myText" value=" " class="form-control" name="cs_tc">
</div>

<div id="cs-pc" class="col-sm-4 text-center">
  <label id="cs-pc-label" class="control-label">Critical Pressure (atm)</label>
  <input type="text" id="myText1" value=" " class="form-control" name="cs_pc">
</div>

<div id="cs-acc" class="col-sm-4 text-center">
  <label id="cs-acc-label" class="control-label">Accentric Factor</label>
  <input type="text" id="myText2" value=" " class="form-control" name="cs_acc">
</div>

<script>
$(document).ready(function() {
  $.ajax({
    type: "GET",
    url: "B1_1.csv", //read csv file
    dataType: "text",
    success: function(data) {processData(data);}
   });
});

function processData(allText) {
 var allTextLines = allText.split("/\r\n|\n/");
 var headers = allTextLines[0].split(',');
 var lines = [];

 for (var i=1; i<allTextLines.length; i++) {
  var data = allTextLines[i].split(',');
  if (data.length == headers.length) {

   var tarr = [];
   for (var j=0; j<headers.length; j++) {
    tarr.push(headers[j]+":"+data[j]);
   }
   lines.push(tarr);
  }
 }
}
</script>

Answer 1

如果我了解您的要求，则不能，无法从html读取文件。使用html中的表单，您可以上传文件，但该事件由javascript处理。

Answer 2

看看W3.JS库。它具有名为W3.data的组件，该组件允许使用JavaScript提取服务器数据。可用于读取JSON和CSV文件的内容。

Answer 3

是的，当然可以，您发布的代码就是这样做的，我知道最初可能会造成混淆，但是让我解释一下javascript部分...

<script> 
// in html you use script tag to put javascript code inside and using jquery, you // can easily modify the html page.

$(document).ready(function() { 
// this is a jquery piece of code that is calling an // ajax request

  $.ajax({
    type: "GET",
    url: "B1_1.csv", //read csv file
    dataType: "text",
    success: function(data) {processData(data);}
   });
});

function processData(allText) { 
// a method is a piece of code that you write once because you know that you will // reuse it and it makes the code more readable

 var allTextLines = allText.split("/\r\n|\n/"); 
// split is a method that takes as input a string and (in this case `allText`) //literally split the calling string in n strings storing them in an array. The //strings are splitted by the string you passed as parameter. In this case this //piece of code is simply dividing the entire text in n lines

 var headers = allTextLines[0].split(','); 
// Now is splitting the line number 1 (look for 0-indexed array on google) in many // strings
 var lines = [];

 for (var i=1; i<allTextLines.length; i++) {
 // A for loop is a loop that repeat itself n-times until a condition is no more 
 // satisfied, in this case i has to be smaller than the length of that array.
 // `var i=1` represents the starting point of the index.
 // `i<allTextLines.length` is the condition and `allTextLines.length` returns the 
 // length of the array.
 // In the end `i++` just increment i every time the loop reach the end and restart

  var data = allTextLines[i].split(',');
  if (data.length == headers.length) {
    // an if statement is a piece of code that is executed if and only if a condition 
    // is satisfied.

   var tarr = [];
   for (var j=0; j<headers.length; j++) {
    tarr.push(headers[j]+":"+data[j]);
   }
   lines.push(tarr); // The push method add to an array a new element
  }
 }
}
</script>

我试图尽我所能地解释（我是一个糟糕的老师，所以这对我来说是训练），希望我能对您有所帮助。如果您有任何疑问，请询问，如果您想更多地使用代码，请在网上查找教程，因为有很多东西。也许您有兴趣，我在here年前就学过javascript。

如何在输入框中显示值

3 个答案: