var instance = new Vintasoft.Twain.WebTwainDeviceJS(deviceName, productFamily, manufacturer, driverVersion, twainVersion, deviceManager, is64Bit);

var value; // Type: any

// Parameters
var successFunc; // Type: function
var errorFunc; // Type: function
var isProgressResponseEnabled; // Type: boolean

value = instance.acquireModalAsync(successFunc, errorFunc, isProgressResponseEnabled);

function acquireModalAsync(
   successFunc
A function that will be executed if request is executed successfully.
 Function prototype: "successFunc(twainDevice, acquireModalResult)", where 'twainDevice' parameter is an instance of WebTwainDeviceJS class, 'acquireModalResult' parameter is an instance of WebTwainDeviceAcquireModalResultJS class.
 : Function, 
   errorFunc
A function that will be executed if request is failed.
 Function prototype: "errorFunc(twainDevice, errorMessage)", where 'twainDevice' parameter is an instance of WebTwainDeviceJS class, 'errorMessage' parameter is string that describes error.
 : Function, 
   isProgressResponseEnabled
A value indicating whether web server should send response for image acquisition progress. Default value is True.
 : boolean
) : any;

Parameters

successFunc

A function that will be executed if request is executed successfully.
Function prototype: "successFunc(twainDevice, acquireModalResult)", where 'twainDevice' parameter is an instance of WebTwainDeviceJS class, 'acquireModalResult' parameter is an instance of WebTwainDeviceAcquireModalResultJS class.

errorFunc

A function that will be executed if request is failed.
Function prototype: "errorFunc(twainDevice, errorMessage)", where 'twainDevice' parameter is an instance of WebTwainDeviceJS class, 'errorMessage' parameter is string that describes error.

isProgressResponseEnabled

A value indicating whether web server should send response for image acquisition progress. Default value is True.

This function sends an asynchronous request to do one step of synchronous image acquisition from TWAIN device. If you want to use synchronous request instead of asynchronous request, please use WebTwainDeviceJS.acquireModalSync function.

Reference

WebTwainDeviceJS Class
WebTwainDeviceJS Members