如何使此javascript函数自动运行？

| 我正在尝试使用经度/纬度转换器来显示OSGR值。这是我目前的代码： 
    <?php

$longitude = \"-0.310150 N\";
$latitude = \"59.688930 W\";
?>

<script language=\"JavaScript\" type=\"text/JavaScript\">
<onload = function() {
           CalculateOSGB();
         };
</script>

<script language=\"JavaScript\" type=\"text/JavaScript\">
function ELMNT(elementName)
{
  return document.getElementById(elementName);
}

function CalculateLL()
{
  ENEN = new EastNorth;
  RefToCoords ( ELMNT(\"OSRef\").value, ENEN );

//  ELMNT(\"OSRef\").value = ELMNT(\"OSRef\").value + ENEN.Easting + \" \" + ENEN.Northing + \"\\t\";
  CoordsToLL(ENEN,LatLong);

  ELMNT(\"latitude\").value = LatLong.Lat;
  ELMNT(\"longitude\").value = LatLong.Long;
//  ELMNT(\"OSRef\").value = ELMNT(\"OSRef\").value + LatLong.Lat + \"\\t\" + LatLong.Long + \"\\t\" + ELMNT(\"OSRef\").value + \"\\n\";
}

function RefToCoords ( InRef, EastNorth )
{
    var  Length1 = 0;
    var  Length2 = 0;
    var  Index;
    Numbers  = new String(\"\");
    Letters  = new String(\"\");
    Easting  = new Array(\"\");
    Northing = new Array(\"\");
    Grid_X = new Array(   0, 100, 200, 300, 400,   0, 100, 200,   0, 300, 400,   0, 100, 200, 300, 400,   0, 100, 200, 300, 400,  0, 100, 200, 300, 400, 0);
    Grid_Y = new Array( 400, 400, 400, 400, 400, 300, 300, 300,   0, 300, 300, 200, 200, 200, 200, 200, 100, 100, 100, 100, 100,  0,   0,   0,   0,   0, 0);
    Lookup = new String(\"                                                                 ABCDEFGHIJKLMNOPQRSTUVWXYZ\");

    Ref = new String(InRef);
    Ref.toUpperCase();

    Length1 = Ref.length;
    for ( i=0; i<Length1; i++ )
    {
        if ( Ref.charAt(i).toUpperCase() >= \'A\' && Ref.charAt(i).toUpperCase() <= \'Z\' )
            Letters = Letters + Ref.charAt(i).toUpperCase();
        else
            if ( Ref.charAt(i) >= \'0\' && Ref.charAt(i) <= \'9\' )
                Numbers = Numbers + Ref.charAt(i);
    }

    if ( Letters.length != 2 )
    {
        ELMNT(\"OSRef\").value = ELMNT(\"OSRef\").value + \"ERROR: OS Ref. Letters must be 2 long\\n\";
        return -1;
    }

    Length2 = Numbers.length;
    if ( !Length2 || Length2 & 0x01 )
    {
        ELMNT(\"OSRef\").value = ELMNT(\"OSRef\").value + \"ERROR: OS Ref. Must not be odd number of numbers\\n\";
        return -1;
    }

    Length2 = Length2 / 2;
    Length2 = Math.floor(Length2)

    Easting = Numbers.slice(0,Length2);
    Easting = Easting + \"00000\";

    Northing = Numbers.slice(5,5+Length2);
    Northing = Northing + \"00000\";

    Index = Lookup.indexOf(Letters.charAt(0)) - 65;
    EastNorth.Easting = 5000 * Grid_X[Index];
    EastNorth.Northing = 5000 * Grid_Y[Index];

    Easting= Easting /100000;
    Northing = Northing / 100000;
    Index = Lookup.indexOf(Letters.charAt(1)) - 65;
    EastNorth.Easting = EastNorth.Easting + ( Grid_X[Index] * 1000 );
    EastNorth.Northing = EastNorth.Northing + ( Grid_Y[Index] * 1000 );

    EastNorth.Easting = EastNorth.Easting + ( parseInt(Easting) - 1000000 );
    EastNorth.Northing = EastNorth.Northing + ( parseInt(Northing) - 500000 );

    return 0;
}

function LLToCoords(LatLong,EastNorth)
{
  var dLongI = 0.0; 
  var dLatI  = 0.0;
  var Rad    = 0.0174532925199432957692369076848;

  dLongI = Rad * (parseFloat ( LatLong.Long )+2.0 );
  dLatI  = parseFloat ( LatLong.Lat ) * Rad;

  dT     = Math.tan ( dLatI );
  dTSq   = dT * dT;
  dJ     = dLongI * Math.cos ( dLatI );
  dJSq   = dJ * dJ;
  dETASq = Math.cos ( dLatI );
  dETASq = dETASq * dETASq * 0.0067153346685;

  dNu = Math.sin ( dLatI );
  dNu = 6377563.396 / Math.sqrt ( 1.0 - ( dNu * dNu * 0.006670539761597 ) );  

  dA7 = ( 61.0 - dTSq * ( 479.0 - 179.0 * dTSq + dTSq * dTSq ) ) /5040.0;
  dA5 = ( 5.0 - dTSq * ( 18.0 - dTSq ) + dETASq * ( 14.0 - 58.0 * dTSq ) ) / 120.0;
  dA3 = ( 1.0 - dTSq + dETASq ) / 6.0;
  dA1 = 0.9996012717 * dNu;

  EastNorth.Easting = dA1 * dJ * ( 1.0 + ( dJSq * ( dA3 + ( dJSq * ( dA5 + dA7 * dJSq ) ) ) ) );

  dM=6335021.60578487*(1.0050342114*dLatI-0.5*0.0050449242*Math.sin(2.0*dLatI)+0.25*0.0000105505*Math.sin(4.0*dLatI));
  dA2 = 0.5 * dA1 * dT;
  dA4 = ( 5 - dTSq + dETASq*(9.0+4.0*dETASq) ) / 12.0;
  dA6 = ( 61.0 - dTSq*(58.0+dTSq) + dETASq*(270.0-330.0*dTSq) ) / 360.0;

  EastNorth.Northing = 0.9996012717 * dM + dA2 * dJSq * ( 1.0 + dJSq * ( dA4 + dA6 * dJSq ) );

  EastNorth.Easting  = EastNorth.Easting + 400000;
  EastNorth.Northing = EastNorth.Northing - 5527063.0;

  return dLongI;
}

function EastNorth(East,North)
{
  this.Easting = East;
  this.Northing = North;
  return 0;
}

function LatLong(Lat,Long)
{
  this.Lat = Lat;
  this.Long = Long;
  return 0;
}

function CoordsToLL(InEastNorth,InLatLong)
{
  var Rad = 0.0174532925199432957692369076848;
  var K = 1 / (  Rad * 6377563.396 );
  var dx;
  var dy;
  var myloop = 0;

  EN = new EastNorth(InEastNorth.Easting,InEastNorth.Northing);
  LL = new LatLong(52.0,-3.0);
  do
  {
    myloop = myloop + 1;
    LLToCoords(LL,EN);
    dx = InEastNorth.Easting - EN.Easting;
    dy = InEastNorth.Northing - EN.Northing;
    LL.Lat = LL.Lat + dy * K;
    LL.Long = LL.Long + dx * K / ( Math.cos(Rad) * LL.Lat );
  } while ( ( ( (Math.abs ( dx ) + Math.abs ( dy )) > 0.0000001 )) && myloop < 5000);
  InLatLong.Lat = LL.Lat;
  InLatLong.Long = LL.Long;

  return 0;
}


function CalculateOSGB()
{

  var lat = \"<?php echo $latitude; ?>\";
  var lon = \"<?php echo $longitude; ?>\";
  LatLong.Lat  = (lat);
  LatLong.Long = (lon);
  LLToCoords ( LatLong, EastNorth );
  ELMNT(\"OSRef\").value = OSReference ( EastNorth );

}


function OSReference(EastNorth)
{
  var Codes = new Array ( \'V\',\'W\',\'X\',\'Y\',\'Z\',\'Q\',\'R\',\'S\',\'T\',\'U\',\'L\',\'M\',\'N\',\'O\',\'P\',\'F\',\'G\',\'H\',\'J\',\'K\',\'A\',\'B\',\'C\',\'D\',\'E\');
  var East = 0.0;
  var North = 0.0;
  var I = 0;
  var J = 0;
  var A = \' \';
  var B = \' \';

  East  = parseInt ( EastNorth.Easting ) + 1000000.0;
  North = parseInt ( EastNorth.Northing ) + 500000.0;

  I = parseInt ( East  / 500000 );
  J = parseInt ( North / 500000 );
  A = Codes[parseInt ( I + J*5 )];

  East  = parseInt (  East % 500000 );
  North = parseInt ( North % 500000 );
  I = parseInt ( parseInt ( East  ) / 100000 );
  J = parseInt ( parseInt ( North ) / 100000 );
  B = Codes[parseInt ( I + J*5 )];

  C = (parseFloat(East)+100000)+\"\";
  D = (parseFloat(North)+400000)+\"\";

  return A + B + \' \' + C.substring(C.length-5,6) + \' \' + D.substring(D.length-5,6);
}
</script>


<div id=\"Layer3\" style=\"position:absolute; width:695px; height:115px; z-index:1; left: 189px; top: 115px;\"> 
  <table align=\"center\" border=\"0\">
    <tbody><tr> 
      <td><font face=\"Arial, Helvetica, sans-serif\">Latitude:</font></td>
      <td><font face=\"Arial, Helvetica, sans-serif\"> 
        <input value=\"\" id=\"latitude\" name=\"latitude\" size=\"30\" type=\"text\">
        </font></td>
      <td><font face=\"Arial, Helvetica, sans-serif\">6° South should be entered 
        as -6.0</font></td>
    </tr>
    <tr> 
      <td><font face=\"Arial, Helvetica, sans-serif\">Longitude:</font></td>
      <td><font face=\"Arial, Helvetica, sans-serif\"> 
        <input value=\"\" id=\"longitude\" name=\"longitude\" size=\"30\" type=\"text\">
        </font></td>
      <td><font face=\"Arial, Helvetica, sans-serif\">4° West should be entered 
        as -4.0</font></td>
    </tr>
    <tr> 
      <td></td>
      <td> <font face=\"Arial, Helvetica, sans-serif\"> 
        <input value=\"Convert Lat/Long to OSGB\" onclick=\"CalculateOSGB()\" name=\"LL2OSGB\" type=\"button\">
        </font></td>
      <td> <font face=\"Arial, Helvetica, sans-serif\"> 
        <input value=\"Convert OSGB to Lat/Long\" onclick=\"CalculateLL()\" name=\"OSGB2LL\" type=\"button\">
        </font></td>
    </tr>
    <tr> 
      <td><font face=\"Arial, Helvetica, sans-serif\">OS Ref.</font></td>
      <td colspan=\"2\"><font face=\"Arial, Helvetica, sans-serif\"> 
        <input value=\"\" id=\"OSRef\" name=\"OSRef\" size=\"30\" type=\"text\">
        </font></td>
    </tr>
    <tr> 
      <td></td>
      <td colspan=\"2\"><font face=\"Arial, Helvetica, sans-serif\">If you see \'NaN\' 
        your Lat/Long is out of range for an OSGB reference</font></td>
    </tr>
  </tbody></table>
  <div id=\"results\" style=\"position:absolute; width:695px; height:50;\"></div>
</div>
我不太了解javascript，但是我相信单击calculate按钮后，calculateOSGB（）函数可以计算出OSGR。有人可以解释一下我如何使它自动运行，而不必单击按钮吗？我希望能够从数据库中插入经度和纬度（为什么要使用PHP变量），并使该脚本自动显示并输出OSGR值。 谢谢你的帮助
2020-06-12 3 条评论
分享

没有找到相关结果

    已邀请:

    氮顺

    如果您不使用jQuery之类的JS库，则可以使用
    onload
     
    onload = function() {
           // do something here
         };
    就是这样。有些人喜欢使用
    window.onload
    ，但这是同一回事。 参考： https://developer.mozilla.org/en/DOM/window.onload 使用window.onload的最佳实践 如果您考虑使用jQuery或其他库，从长远来看，它可以节省您的时间。如果使用jQuery，则可以使用 
    $(function() {   
  // do something
});
    它将在DOM准备就绪时运行，这要比上述第一种方法完全加载页面时早。
    2020-06-12 0 0
    分享

    翱抹村

    有两种方法可以实现此目的，可以使用ѭ5call调用该函数-主体加载后将执行该函数。 您的另一个选择是使用jQuery之类的库，并在加载DOM后使用$（document）.ready（function（）来调用函数。 希望能有所帮助。
    2020-06-12 0 0
    分享
    为什么被折叠? 0 个回复被折叠

    要回复问题请先登录或注册

    或代码 OrCode.com 备案号：粤ICP备15020848号-1
    Escape time: 0.058486938476562