Hi, How can I open the task window(opened in popup) maximized?...

Only using JS. I created a function that tries to resize the window to match the content but not exceed screen size.

function adjustWindowHeight(max) {
setTimeout(function() {

if(max == null) {
max = screen.availHeight - (typeof window.screenTop == 'undefined' ? window.screenY + 90 : window.screenTop) - 20;
}
var currentHeight = document.documentElement.clientHeight;
var neededHeight = document.getElementById("environmentContent").offsetHeight + 25;
if(neededHeight > max) {
neededHeight = max
}

window.resizeBy(0, neededHeight-currentHeight);
}, 250);
}

Put this in onload event of the form.