Question

我正在基于一些我想要的Json数据的计算器，当我输入经度和纬度时，我得到了与该经度和纬度相关联的网格代码。问题是当我从输入中获得值时，结果递归为0表示输入值未定义

这就是我的代码的样子

<!DOCTYPE html>
<html>
<head>

</head>
<body>


<form action="" id="my-form">
  <div class="form-group">
    <label for="">Enter Lat</label>
    <input type="text" id="lat" step="any">
    <label for="">Enter Long</label>
    <input type="textr" id="long" step="any">

  </div>
  <input type="button" id="Btn" value="Calculate" >
  <h2 id="result">result</h2>
</form>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>
var desiredLat = document.getElementById("lat").value,
desiredLong = document.getElementById("long").value;
  const
  myData = {
   "datagrid": [
     { "GRIDCODE": 1735,"lat": 35.91511132, "long": -5.401484264 },
     { "GRIDCODE": 1805, "lat": 35.90677815, "long": -5.468149593 },
     { "GRIDCODE": 1808, "lat": 35.90677815, "long":-5.459816427 },
     { "GRIDCODE": 1784, "lat": 35.89844499, "long":-5.476482759 }
   ]
 };

  gridcode = lookupGridcodeByLatAndLong(myData.datagrid),
  headerHTML = gridcode ;
console.log(headerHTML);



function lookupGridcodeByLatAndLong(sourceArray){
  let gridcode = 0;
  
  for (let currentObject of sourceArray){
    if (currentObject.lat === desiredLat && currentObject.long === desiredLong){
      gridcode = currentObject.GRIDCODE;
    }
  }
 
  return gridcode;
}
$("#Btn" ).click(function() {
  $("#result").html(gridcode);
});

</script>
</body>
</html>

Answer 1

获得zero值的原因是因为您在第一次传递lookupGridcodeByLatAndLong和lat值时调用了lang函数，两个值都将返回未定义因为您尚未输入它们。

您必须先用值填充它们，然后单击按钮以获取lat和lang值，然后再进行计算以获取GRIDCODE，实际上您并不需要可以将对象值解析为参数，因为您已将其初始化为全局参数，因此您仍可以在函数内部使用它而无需解析它。

<!DOCTYPE html>
<html>
<head>

</head>
<body>


<form action="" id="my-form">
  <div class="form-group">
    <label for="">Enter Lat</label>
    <input type="text" id="lat" step="any">
    <label for="">Enter Long</label>
    <input type="textr" id="long" step="any">

  </div>
  <input type="button" id="Btn" value="Calculate" >
  <h2 id="result">result</h2>
</form>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>
  const
  myData = {
   datagrid: [
     { "GRIDCODE": 1735,"lat": 35.91511132, "long": -5.401484264 },
     { "GRIDCODE": 1805, "lat": 35.90677815, "long": -5.468149593 },
     { "GRIDCODE": 1808, "lat": 35.90677815, "long":-5.459816427 },
     { "GRIDCODE": 1784, "lat": 35.89844499, "long":-5.476482759 }
   ]
 };



function lookupGridcodeByLatAndLong(lat, long){
  let gridcode = 0;
  
  var result = myData.datagrid.find(x => x.lat == lat && x.long == long)
  if (result) {
    gridcode = result.GRIDCODE;
  }
 
  return gridcode;
}
$("#Btn" ).click(function() {
	var lat = document.getElementById("lat").value,
	long = document.getElementById("long").value;
	var result = lookupGridcodeByLatAndLong(lat, long)
  $("#result").html(result);
});

</script>
</body>
</html>

如何获取输入给定值到数组

1 个答案: