十进制字段限制的Django客户端验证

Question

I wanted to limit django model decimal field to 4 places in client side itself meaning field should not allow user to enter more than 4 digits.

I tried below code but its get validate only after save but i need to limit while user entering digits.

unit_price = models.DecimalField(db_column='UNIT_PRICE', max_digits=4, decimal_places=2)

Answer 1

Have you tried using a widget in your Form definition?

unit_price = forms.DecimalField(
    widget=forms.NumberInput(attrs={'step': '0.01', 'min': '0.00', 'max': '99.99' }))

Answer 2

You have to use a little javascript to restrict the user from entering more than 4 digits use the below snippet in forms and javascript files

forms

unit_price = forms.DecimalField(
    widget=forms.NumberInput(attrs={'step': '0.01', 'min': '0.00', 'max': '99.99', onkeypress: 'return isValid(event)'}))

javascript

function isValid(event) {
  var val = document.getElementById('test').value;
  val = val.split('.').join('');
  event = (event) ? event : window.event;
  var charCode = (event.which) ? event.which : event.keyCode;
  if (val.length < 4 || charCode == 8 || charCode == 37 || charCode == 39 || charCode == 46){
     return true;
  }
  else {
     return false;
  }
}

By this way, the user input can be restricted to 4 places on keypress too