How do I enqueue a js file in functions.php for a if lt IE 9 statement? [duplicate]

You can do it in two ways….

Solution One:

<?php
add_action( 'wp_head', 'myscript' );
function myscript(){
   echo '<!--[if lt IE 9]><script src="https://wordpress.stackexchange.com/questions/138051/your_js_file_path"></script><![endif]-->';
};
?>

Solution Two:

<?php 
global $wp_scripts;
wp_register_script( 'jsFileIdentifier', 'YourJsFilePath',  array(),  '3.6.2' );
$wp_scripts->add_data( 'jsFileIdentifier', 'conditional', 'lt IE 9' );
?>