modifying form field values - plz help

siuk · Apr 24, 2002

Hi,

Im trying to make a script which will increment a text form field value by 1 each time a button is pressed.

Here is my code so far:
=======================
<SCRIPT language="JavaScript">
function function1(afield){
var var1 = afield;
var val1 = eval("form1."+var1+".value&quot

var result = val1 + 1;

eval("form1."+var1+".value&quot

= result;

}
</SCRIPT>

<form name=form1>
<p> </p>
<p> </p>
<p> </p>
<input type=text name=field1 value=-2 size="4"><input type=submit value=Work onclick="function1('field1');">
</form>
==================================

This script has errors... does anyone know how i can modify the field value without causing the error 'cannot assign to a function result'

Any help would be greatly appreciated!

Thanks

xutopia · Apr 24, 2002

This is a simple fix for it :

<HTML>
<HEAD>
</HEAD>
<BODY>

<SCRIPT>
function populate(afield)
{
afield.value = parseInt(afield.value) + 1
document.form1.submit();
}
</SCRIPT>

<form name=form1>
<input type=text name=field1 value=-2 size="4">
<input type=button value=Work onclick="populate(document.form1.field1);">
</form>

</BODY>
</HTML>

You have to use parseInt() to make sure the value is treated as a number otherwise it would be treated as text.

I hope this helps. Gary

http://www.xutopia.com

Haran

leehinkleman · Apr 24, 2002

<html>
<head>
<SCRIPT language="JavaScript">
v=-2;
function f1(){
v+=1;
document.form1.field1.value=v;
}
</SCRIPT>
<form name="form1">
<p> </p>
<p> </p>
<p> </p>
<input type="text" name="field1" size=4 value=-2>
<input type="button" value="Work" onclick="f1();">
</form>
</body>
</html>

siuk · Apr 24, 2002

Thanks Very Much.. ParseInt is very cool! : )

Boomerang · Apr 24, 2002

Hi siuk, xutopia,

xutopia, what is the meaning of document.form1.submit(); ? I don't understand this.
With the document.form1.submit(); line it restores the value -2 each time.

Without this line it works fine.

Erik
<!-- My sport: Boomerang throwing !!
This year I will participate at the World Championships in Germany. (

http://www.boomerang2002.com)

!! Many Happy Returns !! -->

xutopia · Apr 24, 2002

the reason Boomerand is that the default value for the field is -2. This means that when the page loads the value you will see is -2. So when you submit the page it refreshes and the default value is once again set to minus two.

<input type=text name=field1 value=-2 size="4">

I hope this helps understand.
Gary

http://www.xutopia.com

Haran

Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

modifying form field values - plz help

siuk

Programmer

xutopia

Programmer

leehinkleman

Programmer

siuk

Programmer

Boomerang

Programmer

xutopia

Programmer

Similar threads

Part and Inventory Search

Sponsor