I have a regular expression where I'm checking if a text entry is numeric. This is Year field and it should accept only integers like 1999 or 2000 etc. But in this case it's also accepting -, +, . etc.
isNumeric = function(b){
return(b-0) == b&&(b+"").replace(/^\s+|\s+$/g,"").length > 0
};
Could you please help me out!!
If you need to accept years of 20th and 21th centuries, a more refined regexp could be
isNumeric = function(b){
return /^(19|20)\d{2}$/.test(b)
};
if you need to accept always a 4-digit year, the regular expression is simply
/^\d{4}$/
and if you need to accept every year from 0 to 9999 (where a trailing 0 is not accepted)
/^(0|[1-9]\d{0,3})$/
better solution is to restrict user to enter key other than Numeric using Javascript Create function like this:
function isNumber(evt) {
evt = (evt) ? evt : window.event;
var charCode = (evt.which) ? evt.which : evt.keyCode;
if (charCode > 31 && (charCode < 48 || charCode > 57)) {
return false;
}
return true;
}
and add onkeypress Event to your Textbox:
<input type="text" class="textfield" value="" id="extra7" name="extra7"
onkeypress="return isNumber(event)" />
Demo: JS Fiddle
You can also restrict user to enter only 4 Numerics by adding maxlength="4" to inbox.
If you wish to validate a range of (positive) years for example 1980 to 2020 where the string '+2000' is not accepted.
isNumeric = function(b){
return /^(198\d|200\d|2020)$/.test(b);
}
This will pass the following tests - it's tested here
Function renamed to yearRange
yearRange = function(b){
return /^(198\d|200\d|2020)$/.test(b);
}
test('Year range validation', function() {
equal( yearRange(1979), false, '1979 returns false');
equal( yearRange(1980), true, '1980 returns true');
equal( yearRange('2000'), true, 'The string 2000 returns true');
equal( yearRange(+2000), true, '+2000 returns true' );
equal( yearRange(-2000), false, '-2000 returns false' );
equal( yearRange('+2000'), false, 'The string +2000 returns false');
equal( yearRange('-2000'), false, 'The string -2000 returns false');
});
you can check it like:
if(!isNaN(parseInt(yourstring))){
}
and using regex you can do:
/^[0-9]+$/i.test(yourstring)
parseInt("+123") == 123
return /\d{4}/.test(b)/^\d{4}$/.test(b)instead.