How to check if HTML input textbox is below a certain number using javascript?

Question

I want to validate an input box using javascript to prevent users from entering above a certain number. I have already done the validation for numbers. How do I prevent users from entering above a certain number? For example, users cannot enter more than 24.

I have tried onkeydown="return (this.value<25)"

HTML

<input type="text" size="2" maxlength="2" onkeydown="return ( event.ctrlKey || event.altKey
                || (47<event.keyCode && event.keyCode<58 && event.shiftKey==false)
                || (95<event.keyCode && event.keyCode<106)
                || (event.keyCode==8) || (event.keyCode==9)
                || (event.keyCode>34 && event.keyCode<40)
                || (event.keyCode==46)
                || (parseInt(this.value, 10)<25))">

I don't think the input's value gets updated until after the key event, but in any case I wouldn't try to do it on keydown (or keyup or keypress), for two reasons: (1) It would be a bit weird from the user's point of view that the number keys higher than 2 only work some of the time, and it may take a while before they realise why; (2) Without using the keyboard the user can still paste in higher numbers (or letters). You should validate onsubmit of the form and/or onchange of the field. — nnnnnn
– nnnnnn, Commented Jul 29, 2011 at 3:15
hmm i think i will take your suggestion! Mods can close this question! — newtodatatables
– newtodatatables, Commented Jul 29, 2011 at 10:24

Joe · Accepted Answer · 2011-07-29 02:58:15Z

1

Be sure to use radix:

return (parseInt(this.value, 10)<25)

answered Jul 29, 2011 at 2:58

Joe

82.9k18 gold badges130 silver badges147 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

newtodatatables Over a year ago

I have tried this.. but it doesnt work, take a look at my updated question. Thanks.

Collectives™ on Stack Overflow

How to check if HTML input textbox is below a certain number using javascript?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related