Submit button enable

SeeIT Solutions

05-28-2005, 08:47 AM

Hi, I was just wondering how to make a submit button enabled when a checkbox is clicked (for a terms and conditions kinda thing).

Thanks

Brandoe85

05-28-2005, 08:59 AM

Try this:

<html>
<head>
</head>
<body>
<form name="myForm" acton="">
Terms:<input type="checkbox" name="chk" onclick="if(this.checked) document.myForm.sub.disabled=false; else document.myForm.sub.disabled=true;"><br>
<input type="submit" name="sub" disabled="true">
</form>
</body>
</html>

SeeIT Solutions

05-28-2005, 09:03 AM

thanks

glenngv

05-30-2005, 11:37 AM

You can simplify the code by using this.form to refer to the form and using the ! (not) operator.
<input type="checkbox" name="chk" onclick="this.form.sub.disabled=!this.checked" />

Kor

05-30-2005, 11:47 AM

Nice shortcut, glenngv

object.attribute=!otherobject.attribute;

I wonder if it works when value of the attribute is not a boolean, example if it is or it is not null

glenngv

05-30-2005, 12:44 PM

If you logical NOT a non-boolean value, the result will be a boolean. The non-boolean value will be internally casted to boolean and then it will be negated. See sample below.

alert(!null); //true
alert(!""); //true
alert(!"blah"); //false
alert(!"0"); //false

These make no difference with these shortcuts that we usually use.

var x=null;
if (x) ...

var y;
if (y) ...