The placeholder attribute is supported in all major browsers, except Internet Explorer.

Can I use input placeholder?

Input elements can sometimes show placeholder text as a hint to the user on what to type in. See, for example, the placeholder attribute in HTML5. The :placeholder-shown pseudo-class matches an input element that is showing such placeholder text.

How do I keep placeholder on Internet Explorer focus?

There is no good way to make placeholder stay on field focus in IE 10+ but if you are trying to replace labels with placeholders then you should take a look at this. It is way to combine placeholders and label to improve user experience.