jquery - How to set attachment compulsory for Imagebutton in javascript -

i have field image. want set compulsory on button click event in javascript.

hereis html

<input type="image" name="imgattach" id="imgattach" src="../images/attachment_1.png" onclick="return imgclick();" /> 

and button code

<input type="submit" name="cmdsave" value="save" onclick="return funsavevalidate();" id="cmdsave" class="button" /> 

note want in javascript.

for more info see js fiddle

<input type="image"> used submit form (similar <input type="submit">), not attach image files (https://www.w3.org/tr/html5/forms.html#image-button-state-(type=image))

in order attach image files , make required field, please use <input type="file" accept="image/*" required>