Judged as a number
The easiest way:
After rounding to determine whether and the original value is equal!
JavaScript's rounding function is: parseint
| The code is as follows |
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| if (parseint (value) ==value)
{ Integer!
} Regular Expression method
function checkrate (input)
{
var re =/^[0-9]+.? [0-9]*$/; Determines whether the string www.111cn.net is a number//judgment positive integer/^[1-9]+[0-9]*]*$/ if (!re.test (Input.rate.value))
{
Alert ("Please enter a number (for example: 0.02)");
Input.rate.focus ();
return false;
}
} The following is a common function function Baseisnotnum (thenum)
{
Judge whether it is a number
if (Basetrim (thenum) = "")
return true;
for (Var i=0;i<thenum.length;i++) {
Onenum=thenum.substring (i,i+1);
if (onenum< "0" | | onenum> "9")
return true;
}
return false;
} function Baseisnotint (Theint)
{
To determine whether an integer
Theint=basetrim (Theint);
if ((theint.length>1 && theint.substring (0,1) = = "0") | | Baseisnotnum (Theint)) {
return true;
}
return false;
} function Baseisnotfloat (thefloat)
{
To determine if a floating-point number
Len=thefloat.length;
dotnum=0;
if (len==0)
return true;
for (Var i=0;i<len;i++) {
Onenum=thefloat.substring (i,i+1);
if (onenum== ".")
dotnum++;
if ((onenum< "0" | | onenum> "9") && onenum!= ".") | | DOTNUM>1)
return true;
}
if (len>1 && thefloat.substring (0,1) = = "0") {
if (thefloat.substring (1,2)!= ".")
return true;
}
return false;} |
positive integer
| The code is as follows |
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To determine whether a string is a number
function checkrate (input)
{
var re =/^[0-9]+.? [0-9]*$/;
if (!re.test (Input.rate.value))
{
Alert ("Please enter a number (for example: 0.02)");
Input.rate.focus ();
return false;
}
}
Java Code Collection Code
To judge a positive integer
function checkrate (input)
{
var re =/^[1-9]+[0-9]*]*$/;
if (!re.test (Input.rate.value))
{
Alert ("Please enter a positive integer");
Input.rate.focus ();
return false;
}
}
To determine whether a number can also call the isNaN function of JS, use
var num;
if (isNaN (num)) {
Alert (' num is not a number ');
}
|
function code for numbers such as floating-point number
| The code is as follows |
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| 1. Some regular expressions for interpreting numeric types are listed below /^d+$///non-negative integer (positive integer + 0)
/^[0-9]*[1-9][0-9]*$///Positive integer
/^ ((-d+) | (0+)) $///Non positive integer (negative integer + 0)
/^-[0-9]*[1-9][0-9]*$///Negative integer
/^-?d+$///Integer
/^d+ (. d+)? $///nonnegative floating-point number (positive floating-point number + 0)
/^ ([0-9]+. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*. [0-9]+) | ([0-9]*[1-9][0-9]*)] $///Positive floating-point numbers
/^ (-d+ (. d+)?) | (0+ (. 0+)?)) $///non-positive floating-point number (negative floating-point number + 0)
/^ (-([0-9]+. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*. [0-9]+) | ([0-9]*[1-9][0-9]*))] $///Negative floating-point number
/^ (-?d+) (. d+)? $///floating-point number 2. How to use in a program var r =/^[0-9]*[1-9][0-9]*$///Positive integer
R.test (str); STR for you to judge the character execution returns the result true or false 3. Test a regular function, can be used to determine the number of characters date Email JS function function Testrgexp (Re, s) {//Parameter description Re is regular expression s for the character to be judged
return Re.test (s)
} 4. Function application <script type= "Text/javascript" >
function Testrgexp (Re, s) {//Parameter description Re is regular expression s for the character to be judged
return Re.test (s)
}
var re =/^[0-9]*[1-9][0-9]*$/;
To determine whether a positive integer note: The program is the expression format:/The above regular expression (without double quotes)/
var s = prompt ("Please enter the character to be judged", 10);
var result = Testrgexp (re, s); Test returns TRUE or False
alert (result);
</script> |
