javascript当中parseFloat用法

parseFloat
马克- to-win：马克 java社区：防盗版实名手机尾号： 73203。
例 4.3.1


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
</head>
<BODY>
<SCRIPT LANGUAGE="JavaScript">
<!--
/* 马克-to-win
parseFloat() (Function/global)
Parse a string to extract a floating-point value.
Property/method value type: Number primitive
JavaScript syntax: - parseFloat(aNumericString)
Argument list: aNumericString A meaningful numeric value.
The parseFloat() function returns a numeric value is returned, unless the string cannot be resolved to a meaningful value in which case NaN is returned instead.
It produces a number value dictated by interpreting the contents of the string as if it were a decimal literal value. During conversion parseFloat() ignores leading whitespace characters so you don't have to remove them from the string before conversion takes place.
Note that parseFloat() will only process the leading portion of the string. As soon as it encounters an invalid floating-point numeric character it will assume the scanning is complete. It will then silently ignore any remaining characters in the input argument.
*/
    var x = parseFloat("727.079")
    var y = parseFloat("77.079xyz")
    var z= parseFloat("xyz77.079")
    document.write("x="+x+",y="+y+",z="+z)
//-->
</SCRIPT>

</BODY>
</HTML>


输出结果：
x=727.079,y=77.079,z=NaN