I believe the following should work just fine:

<?php $doc = JFactory::getDocument(); ?>
<!--[if lt IE 9]>
<?php
    $doc->addScript('https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js');
    $doc->addScript('https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js');
?>
<![endif]-->

Note that I've defined $doc outside the statement, just in case you require it elsewhere.

##Update for example:

<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->

<jdoc:include type="head" />

Hope this helps

I believe the following should work just fine:

<?php $doc = JFactory::getDocument(); ?>
<!--[if lt IE 9]>
<?php
    $doc->addScript('https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js');
    $doc->addScript('https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js');
?>
<![endif]-->

Note that I've defined $doc outside the statement, just in case you require it elsewhere.

Update for example:

<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->

<jdoc:include type="head" />

Hope this helps

I believe the following should work just fine:

<?php $doc = JFactory::getDocument(); ?>
<!--[if lt IE 9]>
<?php
    $doc->addScript('https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js');
    $doc->addScript('https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js');
?>
<![endif]-->

Note that I've defined $doc outside the statement, just in case you require it elsewhere.

Hope this helps

I believe the following should work just fine:

<?php $doc = JFactory::getDocument(); ?>
<!--[if lt IE 9]>
<?php
    $doc->addScript('https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js');
    $doc->addScript('https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js');
?>
<![endif]-->

Note that I've defined $doc outside the statement, just in case you require it elsewhere.

##Update for example:

<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->

<jdoc:include type="head" />

Hope this helps