Boolean Function Parameter

I have a simple JS function that I want to return a true or false value
based on the parameter passed in. At this point of time I receive the
error "'True' is undefined". Here is my code below.

JS Function -

function ShowSpecifiedPeriod(pShowPeriod){
document.mfperformance.ShowPeriod.value = pShowPeriod
document.mfperformance.method = 'get'
document.mfperformance.action = 'composite_requestdata.asp'
document.mfperformance.submit();
}

ASP Event Handler -

onclick="ShowSpecifiedPeriod(<%If bShowPeriod = false then
Response.Write true else Response.Write false%>)"

The ASP variable bShowPeriod is set based on the hidden form field
"ShowPeriod" and the initial value is set to false.

More than likely this has to do with the boolean Parameter but I am not
sure how to handle this in JS. I have tried the following but receive
the same results.

function ShowSpecifiedPeriod(boolean pShowPeriod) - Same Error
function ShowSpecifiedPeriod(pShowPeriod boolean) - Same Error

Please let me know what I am doing wrong here.