<script>
function check1(str){return /^-?\d+(\.(\d+))?$/.test(str)}
alert(check1("a.23"))
alert(check1("1.23"))
alert(check1("-23"))
alert(check1("+23"))
</script>
function check1(str){return /^-?\d+(\.(\d+))?$/.test(str)}
alert(check1("a.23"))
alert(check1("1.23"))
alert(check1("-23"))
alert(check1("+23"))
</script>
function check1(str){return /^\d+px$/.test(str)}
alert(check1("apx"))
alert(check1("12"))
alert(check1("12px"))
</script>
function check1(str){return /^#[0-9a-f]{6}$/i.test(str)}
alert(check1("#12345"))
alert(check1("#123def"))
alert(check1("#123defa"))
</script>