10 examples of 'onsubmit form validation' in JavaScript

32
function validateForm() {
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	var  user = document.forms["myForm"]["user"].value;
34
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	if(user.trim() == "") {
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		document.getElementById("userError").innerHTML = "Remplir le champ svp !";
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		return false;
38
	}
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	return true;
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}

177
function validateForm() {
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  if ($("input#username").val() && $("input#password").val()) {
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    return true;
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  } else {
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    return false;
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  }
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}

86
function validate(form) {
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	if(jQuery("#access_id").val() == '') {
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		jQuery("#access_id").parent().parent().addClass('has-warning');
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		return false;
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	} else if(jQuery("#access_key").val() == '') {
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		jQuery("#access_key").parent().parent().addClass('has-warning');
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		return false;
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	} else if(jQuery("#bucket").val() == '') {
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		jQuery("#bucket").parent().parent().addClass('has-warning');
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		return false;
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	} else if(jQuery("#hostname").val() == '') {
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		jQuery("#hostname").parent().parent().addClass('has-warning');
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		return false;
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	}
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	return true;
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}

85
function validate(form) {
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	var i = 0;
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	jQuery("input.required").each(function() {
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		if(jQuery(this).val() == '') {
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			jQuery(this).focus();
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			return false;
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		}
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		i++;
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	});
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	if(i < jQuery("input.required").length) {
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		return false;
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	} else {
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		return true;
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	}
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}

22
validateForm() {
23
  return this.state.username.length > 0 && this.state.password.length > 0 && this.state.confirmPassword.length > 0 && this.state.password === this.state.confirmPassword;
24
}

17
function validateForm()
18
{
19
	var message = "";
20
	var returnValue = true;
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	var fm = document.getElementById("fm");
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	if(fm.firstName.value == "")
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	{
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		message += "- The field First Name is Mandatory \n";
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		returnValue = false;
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	}
27
	if(fm.lastName.value == "")
28
	{
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		message += "- The field Last Name is Mandatory \n";
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		returnValue = false;
31
	}
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	if(fm.email.value == "")
33
	{
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		message += "- The field Email is Mandatory \n";
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		returnValue = false;
36
	}
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	if(!returnValue)
38
	{
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		message = "Please correct the following errors:\n\n" + message;
40
		alert(message);
41
	}
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	return returnValue;
43
}

56
function validateForm () {
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	if (checkField('#name', 'Name')  &&
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	    checkField('#email', 'Email')  &&
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	    checkEmail('#email')  &&
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	    checkField('#message', 'Message')) {
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		return true;
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	}
63
	return false;
64
}

205
function validateForm(form) {
206
  if (form.elements[0].value.length === 0) {
207
    const $form = $(form);
208
    if (!$form.hasClass('errors')) {
209
      $form
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        .addClass('errors')
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        .find('input')
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        .addClass('error')
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        .attr('aria-invalid', 'true');
214
      $(
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        `<div>${Drupal.t(
216
          'Please provide a name for the button group.',
217
        )}</div>`,
218
      ).insertAfter(form.elements[0]);
219
    }
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    return true;
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  }
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  return false;
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}

50
function validateForm(){
51
  var form = document.forms["signup"];
52
  
53
  var result = validate({
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    "email": form["email"].value,
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    "name": form["name"].value,
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    "password": form["password"].value,
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    "confirmPassword": form["confirm_password"].value,
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    "englishName": form["english_name"].value,
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    "class": form["class"].value
60
  }, constraints, {fullMessages: false});
61
  
62
  if(!!result){
63
    // alert only first error message.
64
    alert(result[Object.keys(result)[0]][0]);
65
    return false;
66
  } else {
67
    return true;
68
  }
69
}

8
function validateForm(f)
9
{
10
    if ((!f.scm_integration[0].checked) && (!f.scm_integration[1].checked))  {
11
        alert('{/literal}{t escape=js}Please choose whether the SCM integration feature should be enabled or not.{/t}{literal}');
12
        return false;
13
    }
14
    if (f.scm_integration[0].checked) {
15
        field = getFormElement(f, 'checkout_url');
16
        if (isWhitespace(field.value)) {
17
            alert('{/literal}{t escape=js}Please enter the checkout page URL for your SCM integration tool.{/t}{literal}');
18
            selectField(f, 'checkout_url');
19
            return false;
20
        }
21
        field = getFormElement(f, 'diff_url');
22
        if (isWhitespace(field.value)) {
23
            alert('{/literal}{t escape=js}Please enter the diff page URL for your SCM integration tool.{/t}{literal}');
24
            selectField(f, 'diff_url');
25
            return false;
26
        }
27
        field = getFormElement(f, 'scm_log_url');
28
        if (isWhitespace(field.value)) {
29
            alert('{/literal}{t escape=js}Please enter the log page URL for your SCM integration tool.{/t}{literal}');
30
            selectField(f, 'scm_log_url');
31
            return false;
32
        }
33
    }
34
    return true;
35
}