我不了解js“ $ {method_name}”的某些语法

Question

Here is the code i didn't understand the some syntax like ${method_name} what we are doing by passing the method name to curly braces.

  global._jsname.prototype.createEELayer = function (ftRule) {
  if (this.EELayer) { return; }
  var that = this;
  var myStyle = new OpenLayers.Style ({
  externalGraphic : 'images/man.png',
  graphicOpacity : "${opac}",
  cursor : "pointer",
  graphicWidth : "20px",
  label:"${labelNumber}",
  graphicHeight : "20px",
  graphicYOffset : -9,
  graphicXOffset : -12,
  graphicTitle: "Drag me to move along the route"
 },
{ context :{ 
opac : function (feature) { 
  if (feature.editOpacity) {
    return feature.editOpacity;
  } else {
    return "1.0";
  }
}
,labelNumber : function (feature) {
  var labelNo = feature.data.stopN;
  return labelNo;
}
} 
});

this.EELayer = new OpenLayers.Layer.Vector("EELayer",{ 
styleMap: new OpenLayers.StyleMap({
  "default" : myStyle,
  "onSelect":myStyle
}), 
isBaseLayer : false
});
this.mbox.map.addLayer(this.EELayer);
}

One more thing i didn't get is why method name (labelNumbber) is given in ${labelNumber} .

Answer 1

The expression

....
label:"${labelNumber}",

....

is defining a property named label which is assigned a string . So, what the meaning of the term "${labelNumber}" in this string is, is up to the programs further logic.

Actually, within these few lines, it has no functionality, as it is only a literal and the property is not used in here.

Answer 2

This is the usuall way to pass dinamic variable from PHP to html/js {$method_name} .
So this variables/names probably come from other part of your code that reuse the curent file as template.

Answer 3

maybe a spring MVC Languange I use it often

http://www.mkyong.com/spring-mvc/spring-mvc-hello-world-example/

seen number 4, it can be used in js also