Nothing
get_Sequences = function(x,filename){res = getURL(paste("https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=nuccore&id=",paste(x,collapse=","),"&rettype=fasta",sep=""));write(res,file=paste(filename,"_sequences_fasta.txt"))}
Any scripts or data that you put into this service are public.
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.