PHP - Ejecutar función de JavaScript desde PHP

script language= javascript type= text/javascript >

MiFuncionJS()

{  alert (" EXITO")}

</script >

<?php

codigo que invoca MiFuncionJS

?>

script language= javascript type= text/javascript >

MiFuncionJS()

{  alert (" EXITO")}

</script >

<?php

echo "<script>";

echo "MiFuncionJS();";

echo "</script>";

?>

<script language="javascript" type="text/javascript">

function MiFuncionJS()

{  alert ("EXITO");

}

</script>

<?php

echo "<input type='button' value='Click' onClick='MiFuncionJS();' /><br>";

?>