Formulaire et javascript

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<html>
<head>
<title>Untitled</title>
<script>
function checkValue(){
var inputFields = document.forms[0].getElementsByTagName("input");
var isValid=true;
var isNum = true;
for(var i=0 ; i<inputFields.length && isNum==true; i++){
var inputFieldValue = inputFields[i].value;
isNum= isNumeric(inputFieldValue);
if(isNum==false){
alert("Les données introduites doivent être de type numérique!");
return false;
}
}
document.forms[0].submit;
return true;
}
</script>
<script>
<!-- La fonction isNumeric(sText) provient du site: http://www.codetoad.com/javascript/isnumeric.asp -->
function isNumeric(sText){
var ValidChars = "0123456789.";
var IsNumber=true;
var Char;
for (i = 0; i < sText.length && IsNumber == true; i++){
Char = sText.charAt(i);
if (ValidChars.indexOf(Char) == -1){
IsNumber = false;
}
}
return IsNumber;
}
</script>
</head>

<body>
<form name="myForm" href="./anotherPage.html">
<input type="text" name="id_1" />
<br />
<input type="text" name="id_2" />
<br />
<button type="button" onClick="checkValue();">Envoyer</button>
</form>

</body>
</html>