On SharePoint application page
I am using placeholder in <input> like this:
<input type="text" id="name" name="name" placeholder="your name" />
But placeholder is underlined and says: Validation (XHTML 1.0 transitional) Attribute placeholder is not a valid attribute. But when i put runat = "server", error goes away
<input type="text" id="name" name="name" placeholder="your name" runat="server" />
Now, its valid attribute. I could not understand why placeholder attribute is not valid without runat = "server". Can anybody tell the reason? I did not want to use runat = "server".
I have also added <!DOCTYPE html>at top of the application page, but still it gives same error
You are using HTML5 markup, with XHTML 1.0 Transitional doctype
placeholder, article, footer, etc are all HTML5
Above is the appropriate DOCTYPE for HTML5.