parseInt，parseFloat

document.write(parseInt("10") + "
");  =>  10

document.write(parseInt("10.33") + "
");  =>  10

document.write(parseInt("34 45 66") + "
");  =>  34

document.write(parseInt(" 60 ") + "
");  =>  60

document.write(parseInt("40 years") + "
");  =>  40

document.write(parseInt("He was 40") + "
");  =>  NaN

document.write(parseFloat("10") + "
");  =>  10

document.write(parseFloat("10.33") + "
");  =>  10.33

document.write(parseFloat("34 45 66") + "
");  =>  34

document.write(parseFloat(" 60 ") + "
");  =>  60

document.write(parseFloat("40 years") + "
");  =>  40

document.write(parseFloat("He was 40") + "
");  =>  NaN