Setting Prompt Defaults Dynamically

By | 2015.02.11

For most prompt types in Cognos there is a Default property that allows for setting of static prompt defaults. This allows you to put in a specific value in advance and it works as advertised. However, there are many use cases where we want to dynamically set the default values to make the prompt interface more user-friendly. You might want to default the prompt to a common value that varies but still allow the end-user to change the value to their liking. Clearly, a way to set prompt values dynamically would be helpful.

The most common use for dynamic prompt defaults is setting date prompt initial state. By default, Cognos sets date prompt values to the current date. This includes range prompts where both the From and To date prompt controls will have the current date selected. This is often of little use to the user running the report as data warehouses often have data that is one day behind. In that instance, running a report for the current day would result in no data returned. Setting a common date dynamic date range can go a long way toward providing a richer experience and more user satisfaction with your reports.

The Technique

We will be using run-time JavaScript to set the defaults of a single date prompt which captures a date range for report filtering. The JavaScript outlined will only work in Cognos BI version 10.2 and above as I will only be using the Cognos JavaScript prompt API which wasn’t available in prior versions. This is a standardized way to access prompt objects which is documented and supporting by Cognos. Code written against the API should not break in later versions of Cognos BI.


Before we can reference any Cognos prompt within JavaScript we have to provide a name for the prompt in the prompt object’s Name property. Ideally, the name should conform to JavaScript variable naming conventions. See the JavaScript Identifiers section of the JavaScript Variables Web page for more information. JavaScript compliant names allow us to use the same name to create reference variables in the code. This makes writing and maintaining the code much easier.


For our example code we will assume there is a date prompt on the page named dateRange which has its Range property set to Yes. We will be setting the default values to encompass the previous seven calendar days up to and including the previous day.

The Code

Let’s examine parts of the code in detail.

The Cognos JavaScript API function getControlByName() takes a prompt name and returns the Cognos JavaScript API object that represents that prompt. We assign the object reference to the variable dateRange so that we can use that name going forward. I recommend that you use a variable name that matches the name given the prompt in Cognos, for convenience and easier debugging but this is ultimately up to your own preference.

We create three new date objects to store the current date, the new from date, and the new to date. By subtracting days from the current date we get the from and to dates we want. We take the date objects and convert them to a date string of the format YYYY-MM-DD which is required by the Cognos JavaScript API for date prompts.

We call the addValues() Cognos JavaScript API function against the dateRange object to set the new default values. The function takes a JSON value object indicting the new values to use. For more information on the Cognos JavaScript API value object format see the Cognos documentation.

We don’t need to indicate the display values in the value object we pass in. When setting the value of a prompt with the addValues() function the display value in the value object is ignored. This even holds true for value prompts where use and display values can be different.

We put our code in an if block in order to guarantee that the code only runs once. This is crucial when setting defaults because you want any prompt selections by users to be retained if the page is refreshed or reprompted. For more information on this technique see JavaScript: Running Code Only Once.


Cognos does not provide an easy way to set prompt values dynamically. However, by utilizing the JavaScript API provided by Cognos in version 10.2 and above we have a documented and supported method to manipulate prompts dynamically at run-time using the power of the JavaScript language.

10 thoughts on “Setting Prompt Defaults Dynamically

  1. Rajesh Kaukoti

    i’m looking for java script which helps me to make cognos 11 date prompts display the yesterday date (i.e. today is 11th march, 2020 . it should display 10th march, 2020) can someone help me.

    1. Scott E. Johnson Post author

      Hi. I know how to do this in Cognos 10 but I haven’t had any experience in Cognos 11. I’ve stopped working with Cognos in my day job and use a different BI suite and thus haven’t explored JavaScript on Cognos 11.

  2. Chris Turner

    Hi – I’m sure this will be a basic/obvious question, but this is my first attempt to do anything with JavaScript. Are there any assumptions in your post? I’ve created a very basic prompt page with a prompt on it called dataRange, with the Range property set to Yes.

    I then added a HTML element to the page, and pasted your code into it. I haven’t done anything else. When I run the prompt page the code is displayed as text, and the date is still defaulted to today’s date. I’m guessing I’m missing something fundamental (which will presumably be obvious to you), but I don’t know what.

    1. Scott E. Johnson Post author

      Hi. What version of Cognos are you using? The examples on this site are for Cognos 10. They make work on later versions but it’s not been tested.

  3. Shaik

    var dDate = new Date();
    //Subtract one day
    pickerControlStartDate.setValue(getFormatDate(dDate, 0 , ‘YMD’));

    this code is not working as default date for yesterday in cognos date prompt…appriciate your help

  4. Juan Gonzalez

    Since Cognos 11.0.4 you need to use Custom Controls instead of HTML Items

    1. Scott E. Johnson Post author

      OK. I’m sure people trying to adapt this can make that change. I don’t have access to Cognos 11 so all of my solutions were tested on 10.2+.

  5. Steve

    Can’t get this to work. I added an HTML item containg the java script but dates continue to default to “today”


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