onChange validation for submit

For a field I have validation for onChange() event. When I change the field and click on submit button. Does the onChange() events checks the validation.

In my case it is not checking.

Any help or suggestions please

<textarea id='abc' name='abc' onChange="checkvalidation('abc','true')>ddd</textarea>

function checkvalidation(field, numericOrNot){
var Value = '#' + field;
    var fieldval = $(field).v开发者_C百科al();
    if(numericOrNot) {
        if(isNaN(fieldval)) {
            alert("not a number");
            return false;
        }
    }
    return true;
}

The onChange event should fire when you've changed the value of a form field and remove focus from that field. It should fire before you click the submit button.

However, you're missing a closing quote after the ) in your html.

<textarea id='abc' name='abc' onChange="checkvalidation('abc','true')">ddd</textarea>
//-------------------------------------------------------------------^

Here's how to change your code so that it uses a data- attribute to determine the data type.

Html

<textarea id='abc' name='abc' data-type="number">ddd</textarea>

jQuery Code

$("#abc").change(function() {
  var $this = $(this);
  if($this.data("type") == "number") {
    if(isNaN($this.val())) {
      alert("not a number");
    }
  }
});

Example on how to run this code when the form is submitted

$("form").submit(function(e) {
  var $this = $("#abc");
  if($this.data("type") == "number") {
    if(isNaN($this.val())) {
      alert("not a number");
      e.preventDefault();
    }
  }
});