Why I can´t use a script tag ? -OJS 3.1.1.4-

Hello there, my question is : I can use script tag in the page ?, I need use a little script in the footer for example:

but the text editor delete this part of the code html:
image

I use the option of source code:
image
save it and after open it:
image

Hi @ypz, please review this thread and additionally see if this plugin will be of any use for you.