check if jquery has been loaded, then load it if false

Question

Does anyone know how to check if jquery has been loaded (with javascript) then load it if it hasnt been loaded.

something like

if(!jQuery) {
    //load jquery file
}

Answer 1

Maybe something like this:

<script>
if(!jQuery)
{
   var script = document.createElement('script');
   script.type = "text/javascript";
   script.src = "path/to/jQuery";
   document.getElementsByTagName('head')[0].appendChild(script);
}
</script>