Onchange Work With DOM

I've written some kind of menu to display a diagram with input fields
for a budget plan. A user should be able to change values, which are initially filled by
a database value, and get all corresponding values filled by the
program.

//value given by database
showText[k].setAttribute("value", eval("liste[i][TEXT" + k + "]"));

//onchange event for the user to change the value
showText[k].setAttribute("onchange", "calculate('cost" + i + "')");

//function to recalculate corresponding values
function calculate(myId) {
if (myId == "initial") {
...
}
else {
myId = myId.slice(4);
//getParents(myId) returns corresponding values for myId
var myParents = getParents(myId);
for (var i = deep; i >= 0; i--) {
var sum = 0;
for (var j = 0; j < myParents.length; j++) {
...
for (var k = 0; k < children.length; k++) {
sum +=
parseFloat(document.getElementById(eval("'cost" + children[k] +
"'")).getAttribute("value"));
}}}}}}

My Problem is:
IE and Netscape always use the value initially entered by the database
and not the new value entered by the user.
Is there a timing or DOM problem?