What are the attributes of html datalist tag?

Question

when we type a word in an input box which contain datalist tag. it shows all the words which contain typed letters. (http://www.w3schools.com/tags/tag_datalist.asp in this example when the letter 'a' is typed it shows 'opera' and 'safari')

But what I need is that, when a letter is pressed only the words begin from that letter appears.(In above example when 'a' is entered no suggestion should be appeared) so how can i do that. is there any special attribute in datalist tag for this task ?

thank you