creating folder in document library using jsom

Question

I am trying to create a new folder inside a document library using JSOM, below is my code

var requestUri = _spPageContextInfo.webAbsoluteUrl + "/_api/web/folders";
function getFormDigest(webUrl) {
    return $.ajax({
        url: webUrl + "/_api/contextinfo",
        method: "POST",
        headers: { "Accept": "application/json; odata=verbose" }
    });
}

$("#btnClick").click(function(){
return getFormDigest(_spPageContextInfo.webAbsoluteUrl).then(function (data) {

            return  $.ajax({
                url: requestUri,
                type: "POST",
                data:JSON.stringify({'__metadata': { 'type': 'SP.Folder' }, 'ServerRelativeUrl': '/Documents/NewFoldername'}),
                headers: {
                "accept":"application/json;odata=verbose",
                "content-type": "application/json;odata=verbose",
                "X-RequestDigest": data.d.GetContextWebInformation.FormDigestValue
                },
                success: onSuccess,
                error: onError
                });

                function onSuccess(data) {
                alert('Folder created successfully');
                }

                function onError(error) {
                alert(JSON.stringify(error));
                }

                });


    });

});

I am getting the below error

"{"readyState":4,"responseText":"{\"error\":{\"code\":\"-2147024809, System.ArgumentException\",\"message\":{\"lang\":\"en-US\",\"value\":\"Value does not fall within the expected range.\"}}}","responseJSON":{"error":{"code":"-2147024809, System.ArgumentException","message":{"lang":"en-US","value":"Value does not fall within the expected range."}}},"status":400,"statusText":"Bad Request"}"

Answer 1

As per the comment, It was URL issue. Valid URL is

Shared Documents/NewFolderName

Sabita S added another fix:

Remove backslash (/) from data relative URL .It should be 'ServerRelativeUrl': 'Documents/NewFoldername' .... data:JSON.stringify({'__metadata': { 'type': 'SP.Folder' }, 'ServerRelativeUrl': 'Documents/NewFoldername'})