.CodeMirror { border: 1px solid silver; } .CodeMirror-empty { outline: 1px solid #c22; } .CodeMirror-empty.CodeMirror-focused { outline: none; } .CodeMirror pre.CodeMirror-placeholder { color: #999; }
CodeMirror
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Placeholder
Placeholder demo
The placeholder plug-in adds an option placeholder that can be set to make text appear in the editor when it is empty and not focused. If the source textarea has a placeholder attribute, it will automatically be inherited.
var editor = CodeMirror.fromTextArea(document.getElementById("code"), { lineNumbers: true });