Javascript backslash in php dom object

I'm trying to add some js code (from Openlayers3) to a php dom object. Echoing the html with the js code directly works but not after it is loaded into the dom. I get "SyntaxError: illegal character" in Firefox. I think it's the backslashes in the js code thats the problem. How could I make it work? I've tried htmlspecialchars but it didn't work. <?php $html = '<html><head><script type="text/javascript">'.file_get_contents("http://ol3js.org/en/master/build/ol.js").'</script></head><body></body></html>'; $dom = new DOMDocument(); $dom->loadHTML($html); $html2 = $dom->saveHTML(); echo $html2; //works not // echo $html works ?> /HU