Attribute for
<FORM ...>
<SCRIPT> <!-- function Circle_calc_ii() { var CircleRadius = document.MyCircleForm.Circle_radius.value; if (CircleRadius >= 0) { document.MyCircleForm.Circle_circumference.value = 2 * Math.PI * CircleRadius ; document.MyCircleForm.Circle_area.value = Math.PI * Math.pow(CircleRadius, 2) ; } else { document.MyCircleForm.Circle_circumference.value = ""; document.MyCircleForm.Circle_area.value = ""; } } // --> </SCRIPT> <FORM NAME="MyCircleForm"> <TABLE BORDER CELLPADDING=3> <TR> <TD><NOBR>radius: <INPUT NAME="Circle_radius" SIZE=4></NOBR></TD> <TD><INPUT TYPE=BUTTON OnClick="Circle_calc_ii(this.form);" VALUE="calculate"></TD> <TD ALIGN=RIGHT BGCOLOR="#AACCFF"> <NOBR>circumference: <INPUT NAME="Circle_circumference" SIZE=9></NOBR><BR> <NOBR>area: <INPUT NAME="Circle_area" SIZE=9></NOBR></TD> </TR> </TABLE> </FORM>
It is possible to refer to the form without using
<FORM><!-- note there is no NAME atttibute --> <TABLE BORDER CELLPADDING=3> <!-- circumference and radius of a circle --> <TR> <TD><NOBR>radius: <INPUT NAME="Circle_radius" SIZE=4></NOBR></TD> <TD><INPUT TYPE=BUTTON OnClick="Circle_calc(this.form);" VALUE="calculate"></TD> <TD ALIGN=RIGHT BGCOLOR="#AACCFF"> <NOBR>circumference: <INPUT NAME="Circle_circumference" SIZE=9></NOBR><BR> <NOBR>area: <INPUT NAME="Circle_area" SIZE=9></NOBR></TD> </TR> </TABLE> </FORM> which gives us
Another much worse way to refer to the form without giving it a name is to use the form's index in the forms array. If our form were the first form on this web page, we could refer to it like this:
var CircleRadius = parseFloat(document.forms[0].Circle_radius.value); That would require keeping track of how many forms down on the page it is, and on a page like this that would be way too much trouble. |