There is actual a hack which makes it possible to add multiline placeholders in Webkit browsers, Chrome used to work but in more recent versions they removed it:
First add the first line of your placeholder to the html5 as usual
<textarea id="text1" placeholder="Line 1" rows="10"></textarea>
then add the rest of the line by css:
#text1::-webkit-input-placeholder::after {
display:block;
content:"Line 2\A Line 3";
}
If you want to keep your lines at one place you can try the following. The downside of this is that other browsers than chrome, safari, webkit-etc. don't even show the first line:
<textarea id="text2" placeholder="." rows="10"></textarea>?
then add the rest of the line by css:
#text2::-webkit-input-placeholder{
color:transparent;
}
#text2::-webkit-input-placeholder::before {
color:#666;
content:"Line 1\A Line 2\A Line 3\A";
}
It would be very great, if s.o. could get a similar demo working on Firefox.