openlayers2 开发如何判断一个marker所在的点是否在一个多边形内部

var components = f.geometry.components,//f为OpenLayers_Feature_Vector类型的对象

bottom = f.geometry.bounds.bottom,
top = f.geometry.bounds.top,
left = f.geometry.bounds.left,
right = f.geometry.bounds.right,
components = f.geometry.components;
$.each(markers,function (i,marker) { //markers为所有marker
lat = marker.lonlat.lat,
lon = marker.lonlat.lon;
//判断marker所在的位置是否在多边形内部
if(lat>bottom&&lat<top&&lon>left&&lon<right){//首先判断点是不是在多边形的边界也就是矩形框内部
var k, j, c = 0;
var length = components.length;
for (k = 0, j = length-1; k < length; j = k++) {
if (((components[k].y>lat) != (components[j].y>lat) ) &&
(lon < (components[j].x-components[k].x)*(lat-components[k].y)/(components[j].y-components[k].y)+components[k].x))
c = !c;
}
if(c){
//TODO 进入这个if说明是在多边形内 现在要写自己的逻辑了
}
}
});