import re
s = """
<script>
var i = 1636592595;
var j = i + Number("6876" + "52907");
</script>
"""
pattern = r'var j = i \+ Number\("(\d*)" \+ \"(\d*)\"\);'
m = re.findall(pattern, s)
print(m)
s = """
xhr.send(JSON.stringify({
"bm-foo": "AAQAAAAE/////4ytkgqq/oWI",
"pow": j
}));
"""
pattern = r'"bm-foo": "([^"]*)",'
m = re.findall(pattern, s)
print(m) # Output: []
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