how to call javscript function from code behind

i want to call the javascript function from the code behind until the javascript function process is not completed. should not come back to the code-behind.

below is my code-after getting the resposne from api now need to add value into table and dispaly

var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
all = JsonConvert.DeserializeObject(responseString);
ScriptManager.RegisterStartupScript(this, typeof(Page), "OnClientClicking", "divCloseAcntopen();", true);
GetAllOrders();
IdOfOrder=all.id;
GetordedsdsdsrById(IdOfOrder);

javascript function