In most modern browsers, you should be able to hide placeholders when printing, via some non-standard CSS selectors.
@media print {
::-webkit-input-placeholder { /* WebKit browsers */
color: transparent;
}
:-moz-placeholder { /* Mozilla Firefox 4 to 18 */
color: transparent;
}
::-moz-placeholder { /* Mozilla Firefox 19+ */
color: transparent;
}
:-ms-input-placeholder { /* Internet Explorer 10+ */
color: transparent;
}
}
(or color: white
, etc.)
Selector list stolen from: Change an HTML5 input's placeholder color with CSS