This is an Binary to Decimal Converter That I Can't Seem to Get Working Properly Since The If and If Else Statements Seems to add either state meant = true or not any help would be awesome

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>An XHTML 1.0 Strict standard template</title>
<meta http-equiv="content-type"
content="text/html;charset=utf-8" />
<script type="text/javascript">
var binary = "";
binary = prompt("Enter Binary Number");
alert(binary)
var strArray = binary;
var binaryArray = strArray.split("");
var conversionNumbers = new Array(8)
conversionNumbers[0] = 128
conversionNumbers[1] = 64
conversionNumbers[2] = 32
conversionNumbers[3] = 16
conversionNumbers[4] = 8
conversionNumbers[5] = 4
conversionNumbers[6] = 2
conversionNumbers[7] = 1
var decimal = 0;
if (binaryArray[0] = "1")
{
decimal = decimal + conversionNumbers[0]
}
else if (binaryArray[0] = "0")
{
decimal = decimal
}
alert(decimal)
if (binaryArray[1] = "1")
{
decimal = decimal + conversionNumbers[1]
}
else if (binaryArray[1] = "0")
{
decimal = decimal
}
alert(decimal)
if (binaryArray[2] = "1")
{
decimal = decimal + conversionNumbers[2]
}
else if (binaryArray[2] = "0")
{
decimal = decimal
}
alert(decimal)
if (binaryArray[3] = "1")
{
decimal = decimal + conversionNumbers[3]
}
else if (binaryArray[3] = "0")
{
decimal = decimal
}
alert(decimal)
if (binaryArray[4] = "1")
{
decimal = decimal + conversionNumbers[4]
}
else if (binaryArray[4] = "0")
{
decimal = decimal
}
alert(decimal)
if (binaryArray[5] = "1")
{
decimal = decimal + conversionNumbers[5]
}
else if (binaryArray[5] = "0")
{
decimal = decimal
}
alert(decimal)
if (binaryArray[6] = "1")
{
decimal = decimal + conversionNumbers[6]
}
else if (binaryArray[6] = "0")
{
decimal = decimal
}
alert(decimal)
if (binaryArray[7] = "1")
{
decimal = decimal + conversionNumbers[7]
}
else if (binaryArray[7] = "0")
{
decimal = decimal
}
alert(decimal)
</script>
</head>
<body>
<script>
document.write (binary)
document.write ("The Decimal Of The Binary Number You Entered Is " + decimal)
</script>
</body>
</html>