It seems the minlength attribute for an field doesn\'t work.
Is there any other attribute in HTML5 with the help of which I
Yes, there it is. It's like maxlength. W3.org documentation: http://www.w3.org/TR/html5/forms.html#attr-fe-minlength
In case minlength doesn't work, use the pattern attribute as mentioned by @Pumbaa80 for the input tag.
For textarea:
For setting max; use maxlength and for min go to this link.
You will find here both for max and min.