Validation for textbox that shoud not allow greater than a number

Validation for textbox that shoud not allow greater than a number

I have a text box like,
<input type="text" id="hourField" value=""/>
How can we restrict that text box should not allow greater than 12. (i.e
12hr format, this should allow 1 to 12 numbers only. it should not allow
grater than 12.