how to call call javascript function from page load.

hi i wanted one function in page load . so i can give javascript function in body tag like <body onload="function GridViewRepeatColumns(gridviewid, repeatColumns)); but i already body onload tag for some other purpose. again i wanted call one javascript function on pageload event.
{ScriptManager.RegisterStartupScript(up1, up1.GetType(), "GridViewRepeatColumns", "ScriptManager.RegisterStartupScript(up1, up1.GetType(), "GridViewRepeatColumns", "GridViewRepeatColumns('<%#=toolscat.ClientID %>',3);", true);('<%#=toolscat.ClientID %>',3);", true);
<script type="text/javascript">

hi i am calling jquery function using above line. it invokes that jqury function which is below:
function GridViewRepeatColumns(gridviewid, repeatColumns) {
......
}

but