How to call a javascript file (.js) via Excel VBA?

Set maPageHtml = IE.document
Set Helem = maPageHtml.getElementsByTagName("input")

For i = 0 To Helem.Length - 1
    If Helem(i).getAttribute("name") = "toFind" Then Helem(i).Value = "819971" '819971 is the valeo reference searched
    If Helem(i).getAttribute("name") = "submit" Then Set Monbouton = Helem(i)
Next

Monbouton.Click 'this does the click on my button Monbouton

oIE.Document.frmMain.param1.Value = 5
oIE.Document.frmMain.param2.Value = "6"
oIE.Document.frmMain.submit.click ' this line will call the JavaScript function

<div id="submit" > <a href="javascript:doAction();">Do Action</a></div>

<script>
function doAction()
{
    // do whatever the code should do
}
</script>