You can use JavaScript (e.g. with jQuery) to allow only specific characters:
// Catch all events related to changes
$('#textbox').on('change keyup', function() {
// Remove invalid characters
var sanitized = $(this).val().replace(/[^0-9]/g, '');
// Update value
$(this).val(sanitized);
});
Here is a fiddle.
Same thing with support for floats:
// Catch all events related to changes
$('#textbox').on('change keyup', function() {
// Remove invalid characters
var sanitized = $(this).val().replace(/[^0-9.]/g, '');
// Remove the first point if there is more than one
sanitized = sanitized.replace(/.(?=.*.)/, '');
// Update value
$(this).val(sanitized);
});
And here is another fiddle.
Update: Although you might not need this, here is a solution that allows a leading minus sign.
// Catch all events related to changes
$('#textbox').on('change keyup', function() {
// Remove invalid characters
var sanitized = $(this).val().replace(/[^-0-9]/g, '');
// Remove non-leading minus signs
sanitized = sanitized.replace(/(.)-+/g, '$1');
// Update value
$(this).val(sanitized);
});
3rd fiddle
And now a final solution that allows only valid decimals (including floats and negative numbers):
// Catch all events related to changes
$('#textbox').on('change keyup', function() {
// Remove invalid characters
var sanitized = $(this).val().replace(/[^-.0-9]/g, '');
// Remove non-leading minus signs
sanitized = sanitized.replace(/(.)-+/g, '$1');
// Remove the first point if there is more than one
sanitized = sanitized.replace(/.(?=.*.)/g, '');
// Update value
$(this).val(sanitized);
});
Final fiddle
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