<button id="editor1-button">Insert invalid cell with colspan 0</button>
<br />
<br />
<div id="editor1"></div>

<br />
<br />
<button id="editor2-button">Insert invalid cell with colspan "abc"</button>
<br />
<br />
<div id="editor2"></div>

<br />
<br />
<button id="editor3-button">Insert invalid cell with negative colspan and rowspan</button>
<br />
<br />
<div id="editor3"></div>
