Doind Math operations with PHP on a form

[Arc]

Hi. True newbie here. Just doing something to try and get the hang of this.

I have a Form with 3 txt fields and 1 Submit Button.

I am simply trying to add txtfield1 with textfield2 and display the result in txtfield3 when the Button is clicked.

I am trying to make a php file to handle the math work and the output to the Result field, but i have no clue how to Include it in an OnClick event so it does the math and then outputs the result to the right field.

Also, how do i get the values of the txtfileds and calculate them in the php file?

Any help at all is greatly appreciated😃

[sid]

<?php

if ($action == "calc") {
    $txtfield3 = $txtfield1 + $txtfield2;
}

print "<FORM ACTION=\"$PHP_SELF\" METHOD=\"POST\">
field 1: <INPUT TYPE=\"text\" NAME=\"txtfield1\" VALUE=\"$txtfield1\"><BR>
field 2: <INPUT TYPE=\"text\" NAME=\"txtfield2\" VALUE=\"$txtfield2\"><BR>
field 3 (result): <INPUT TYPE=\"text\" NAME=\"txtfield3\" VALUE=\"$txtfield3\" READONLY><BR>
<INPUT TYPE=\"hidden\" NAME=\"action\" VALUE=\"calc\">
<INPUT TYPE=\"submit\" VALUE=\"Calculate\">
</FORM>";

?>

[psy]

this is something cool i found a while ago, and expression calculator.. it takes an expression (ex: 1+2*(7/8)%2) and does the math for you .. its handy for school 🙂

<?
if($_POST)
{
  if(!eregi("[a-z]",$inexp))
    eval("\$result=" . $inexp . ";");
  else
    $result="invalid";

   echo "Expression: " . $inexp . "<br>";
   echo "Result: "  . $result . "<br><br>";
}
?>
<form method="post" action="<?=$PHP_SELF?>">
Experssion:&nbsp;<input type=text name="inexp" size=40>
<input type=submit value="Calculate">
</form>

be careful with eval though, bc without the eregi check, i could type in the textbox "echo 'hello'" and it would print hello -> not a good thing 🙂

[Arc]

Thanks guys, both of your examples work, but not how i intended for it to work.

See i have the Htm file that has a form on it. On the form are the 3 txtfields and the calculate button.

What i want to happen is that htm file is to show the results.

Your example sid, did what i was asking but it took me to the php page and then i was to calculate it there.

I was using an Include statement in the OnCLick event of the Calculate button. When i click this button i want the php page to do the work and output the result to the txtResult txtfield without taking me to a new page. What i mean is, its ok if the php page has to load to do its work but i want the results shown on the original Htm page not on a seperate php page.

Am i making any sense?😕

I was told javascript would be the best way to do this... but i'm not doing it to be practocle i'm just trying to figure out how this whole Php thing works exactly.😃

Thanks!!😃 🆒 😕

[psy]

heres my 2nd shot , you want it all to be in the same php file right? if so , this is it

<?
if($_POST) // see if user submitted it //
{
 // add them together //
 $retval=$_POST['val1'] + $_POST['val2'];
}
?>
<form action="<?=$PHP_SELF?>" method="post">
<!-- post form to itself (replace $PHP_SELF with page name if you want) -->
<?
// conditional IF statements.. //
// $val=(condition)?true:false;
$result=(isset($retval))?$retval:"";
$v1=(isset($_POST['val1'])?$_POST['val1']:"");
// alternate for $v2 -> setup like $v1, without the conditional
if(isset($_POST['val2'])){
 $v2=$_POST['val2'];
}else{
 $v2="";
}
?>
Number 1:&nbsp;<input type=text name=val1 value="<?=$v1?>" size=10><br>
Number 2:&nbsp;<input type=text name=val2 value="<?=$v2?>" size=10><br>
Result:&nbsp;&nbsp;<input type=text name=result value="<?=$result?>"><br>
<input type=submit value=" Calculate ">
</form>

or do you want (say) calc.htm to pass the numbers to calc.php, have calc.php do the math, then regurgitate the sum back to calc.htm? if you do-it's not such a great idea because think about it: to add 2 fields, you have to reload the page twice (1=going to the php, and 2=coming from the php), it just seems like a pain in the ass, not to mention it would take 2 files to do the job of 1