When Reportviewer page viewed in Firefox or Google Chrome ( Non IE Browsers) sometime it doesn’t load properly , that is just because of DOCTYPE Tag of aspx Page

<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>

Remove DOCTYPE Tag and add following property to Reportviewer will solve the issue of page height

For some case it works by adding

AsyncRendering=”False”

In certain situation it works  using

SizeToReportContent = “True”