Javascript window.open pass values using POST

I have a javascript function that uses window.open to call another page and returning the result.

Here is the section of my code:

var windowFeatures = "status=0, toolbar=0, location=0, menubar=0, directories=0, resizable=1, scrollbars=1";
window.open ('http://www.example.com/index.php?p=view.map&coords=' + encodeURIComponent(coords), 'JobWindow', windowFeatures);

My problem now is that I am passing too much data for the GET to handle and I need to pass it using the POST method.

How can I convert the code above to open the page using the POST method without implement forms all over the page (the page lists 100's of orders with a list of suppliers - I am trying to map the suppliers)

I used a variation of the above but instead of printing html I built a form and submitted it to the 3rd party url:

    var mapForm = document.createElement("form");
    mapForm.target = "Map";
    mapForm.method = "POST"; // or "post" if appropriate
    mapForm.action = "http://www.url.com/map.php";

    var mapInput = document.createElement("input");
    mapInput.type = "text";
    mapInput.name = "addrs";
    mapInput.value = data;
    mapForm.appendChild(mapInput);

    document.body.appendChild(mapForm);

    map = window.open("", "Map", "status=0,title=0,height=600,width=800,scrollbars=1");

if (map) {
    mapForm.submit();
} else {
    alert('You must allow popups for this map to work.');
}

Thank you php-b-grader. I improved the code, it is not necessary to use window.open(), the target is already specified in the form.

// Create a form
var mapForm = document.createElement("form");
mapForm.target = "_blank";    
mapForm.method = "POST";
mapForm.action = "abmCatalogs.ftl";

// Create an input
var mapInput = document.createElement("input");
mapInput.type = "text";
mapInput.name = "variable";
mapInput.value = "lalalalala";

// Add the input to the form
mapForm.appendChild(mapInput);

// Add the form to dom
document.body.appendChild(mapForm);

// Just submit
mapForm.submit();

for target options --> w3schools - Target

For what it's worth, here's the previously provided code encapsulated within a function.

openWindowWithPost("http://www.example.com/index.php", {
    p: "view.map",
    coords: encodeURIComponent(coords)
});

Function definition:

function openWindowWithPost(url, data) {
    var form = document.createElement("form");
    form.target = "_blank";
    form.method = "POST";
    form.action = url;
    form.style.display = "none";

    for (var key in data) {
        var input = document.createElement("input");
        input.type = "hidden";
        input.name = key;
        input.value = data[key];
        form.appendChild(input);
    }

    document.body.appendChild(form);
    form.submit();
    document.body.removeChild(form);
}

thanks php-b-grader !

below the generic function for window.open pass values using POST:

function windowOpenInPost(actionUrl,windowName, windowFeatures, keyParams, valueParams) 
{
    var mapForm = document.createElement("form");
    var milliseconds = new Date().getTime();
    windowName = windowName+milliseconds;
    mapForm.target = windowName;
    mapForm.method = "POST";
    mapForm.action = actionUrl;
    if (keyParams && valueParams && (keyParams.length == valueParams.length)){
        for (var i = 0; i < keyParams.length; i++){
        var mapInput = document.createElement("input");
            mapInput.type = "hidden";
            mapInput.name = keyParams[i];
            mapInput.value = valueParams[i];
            mapForm.appendChild(mapInput);

        }
        document.body.appendChild(mapForm);
    }


    map = window.open('', windowName, windowFeatures);
if (map) {
    mapForm.submit();
} else {
    alert('You must allow popups for this map to work.');
}}

Even though this question was long time ago, thanks all for the inputs that helping me out a similar problem. I also made a bit modification based on the others' answers here and making multiple inputs/valuables into a Single Object (json); and hope this helps someone.

js:

//example: params={id:'123',name:'foo'};

mapInput.name = "data";
mapInput.value = JSON.stringify(params); 

php:

$data=json_decode($_POST['data']); 

echo $data->id;
echo $data->name;