Force user to fill all fields before enabling form

2020-05-30 06:28发布

站内文章 / JavaScript
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问题:

I have a form containing various fields.

See jsFiddle demo.

My aim is to enable the submit button only when the user has filled in all fields.

So far, I'm able to force the title field to have content before submit button is enabled. How do I make it so that all other fields need to be filled too before submit button is enabled. 

    jQuery("input[type='text']").on("keyup", function () {
        if (jQuery(this).val() != "" ) {
            if (jQuery("#titlenewtide").val() != '')
            {
                jQuery("#subnewtide").removeAttr("disabled");
            }
        } else {
            jQuery("#subnewtide").attr("disabled", "disabled");
        }
    });
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="#" method="post" id="new_tide">
        Title: <input id="titlenewtide" type="text" name="title" required> <br>
        Description: <textarea name="description" id="description"></textarea> <br>
        Tag:  <input id="newtag" type="text" name="newtag" required> <br>
        Category: <input type="radio" name="category" value="19" required> Animation
        <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button> 
    </form>

Note that I am loading the JavaScripts in my footer.

回答1:

  • Make the changes take effect after changing inputs values:

On each input change, test the values of other inputs and checked state of radio, if all inputs has been entered it will make the submit button enabled:

var validateInputs = function validateInputs(inputs) {
  var validForm = true;
  inputs.each(function(index) {
    var input = $(this);
    if (!input.val() || (input.type === "radio" && !input.is(':checked'))) {
      $("#subnewtide").attr("disabled", "disabled");
      validForm = false;
    }
  });
  return validForm;
}

inputs.change(function() {
  if (validateInputs(inputs)) {
    $("#subnewtide").removeAttr("disabled");
  }
});

Demo:

var inputs = $("form#myForm input, form#myForm textarea");

var validateInputs = function validateInputs(inputs) {
  var validForm = true;
  inputs.each(function(index) {
    var input = $(this);
    if (!input.val() || (input.type === "radio" && !input.is(':checked'))) {
      $("#subnewtide").attr("disabled", "disabled");
      validForm = false;
    }
  });
  return validForm;
}


inputs.change(function() {
  if (validateInputs(inputs)) {
    $("#subnewtide").removeAttr("disabled");
  }
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="#" method="post" id="myForm">

  Title:
  <input id="titlenewtide" type="text" name="title" required>
  <br>Description:
  <textarea name="description" id="description"></textarea>
  <br>Tag:
  <input id="newtag" type="text" name="newtag" required>
  <br>Category:
  <input type="radio" name="category" value="19" required>Animation
  <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button>

</form>

Also it uses the form id="myForm", so you can use it to validate only specific forms in your pages.

Note: This is tested and working on Chrome, Firefox and IE.

EDIT:

  • Make the changes take effect when we type in the inputs:

In the previous code we are using onchange event handler to call the function so it's only called when we click outside a given input (after change).

To perform the call automatically when the user enters a character in a field (the last one) we need to use the onkeyup event so we don't need to click outside of it.

This is the changed code you need :

    var inputs = $("form#myForm input, form#myForm textarea");

    var validateInputs = function validateInputs(inputs) {
      var validForm = true;
      inputs.each(function(index) {
        var input = $(this);
        if (!input.val() || (input.type === "radio" && !input.is(':checked'))) {
          $("#subnewtide").attr("disabled", "disabled");
          validForm = false;
        }
      });
      return validForm;
    }


    inputs.each(function() {
      var input = $(this);
      if (input.type === "radio") {
        input.change(function() {
          if (validateInputs(inputs)) {
            $("#subnewtide").removeAttr("disabled");
          }
        });
      } else {
        input.keyup(function() {
          if (validateInputs(inputs)) {
            $("#subnewtide").removeAttr("disabled");
          }
        });
      }
    });
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="#" method="post" id="myForm">

  Title:
  <input id="titlenewtide" type="text" name="title" required>
  <br>Description:
  <textarea name="description" id="description"></textarea>
  <br>Tag:
  <input id="newtag" type="text" name="newtag" required>
  <br>Category:
  <input type="radio" name="category" value="19" required>Animation
  <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button>

</form>



回答2:

Use this code below. On each input, it will check all the form fields by using this function validate().

jQuery("input[type='text'], textarea").on("input", function () {
    var isValid = validate();
    if (isValid) {
      jQuery("#subnewtide").removeAttr("disabled");
    } else {
        jQuery("#subnewtide").attr("disabled", "disabled");
    }
});


function validate() {
  var isValid = true;
  $('input, textarea').each(function() {
    if ($(this).val() === '')
        isValid = false;
  });
  return isValid;
}

Fiddle

Update

To make it validate if the form has id="new_tide" and fix about the radio button.

$("input[type='text'], textarea").on("change input", function() {
  validate($(this));
});

$("input:radio[name='category']").on("change", function() {
    validate($(this));
});

function validate(self) {
  if (self.parents("form:first").attr("id") == "new_tide") {
    var isValid = true;
    $('input[type="text"], textarea').each(function() {
      if ($(this).val() === '')
        isValid = false;
    });

    if (!$("input:radio[name='category']").is(':checked'))
      isValid = false;

    if (isValid) {
      $("#subnewtide").removeAttr("disabled");
    } else {
      $("#subnewtide").attr("disabled", "disabled");
    }
  }
}

Fiddle



回答3:

Here's how you can do it:

$(document).ready(function () {
    var $inputs = $("#new_tide input:not([type=hidden]), #new_tide textarea");

    $inputs.on("input change", function () {
        valid = true;
        $inputs.each(function () {
            valid *= this.type == "radio" ? this.checked : this.value != "";
            return valid;
        });    
        $("#subnewtide").prop("disabled", !valid);
    });
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<form action="#" method="post" id="new_tide">
    Title: <input id="titlenewtide" type="text" name="title" required> <br>
    Description: <textarea name="description" id="description"></textarea> <br>
    Tag:  <input id="newtag" type="text" name="newtag" required> <br>
    Category: <input type="radio" name="category" value="19" required> Animation
    Hidden: <input type="hidden">
    <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button> 
</form>



回答4:

Try utilizing .siblings() , .map() to compile values of form elements , Array.prototype.every() to return Boolean representation of input , textarea values , set disabled property of form input[type=submit] element 

$("form *[required]").on("input change", function(e) {
  $(this).siblings("[type=submit]").prop("disabled"
  , !$(this).siblings(":not([type=submit])").add(this).map(function(_, el) {
    return el.type === "radio" ? el.checked : el.value
   }).get().every(Boolean)
  );
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js">
</script>
<form action="#" method="post" id="new_tide">
    Title: <input id="titlenewtide" type="text" name="title" required> <br>
    Description: <textarea name="description" id="description" required></textarea> <br>
    Tag:  <input id="newtag" type="text" name="newtag" required> <br>
    Category: <input type="radio" name="category" value="19" required> Animation
    <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button> 
</form>



回答5:

By far the easiest, would be to rely on the HTML5 validation you're already using.

You'd have to add required to all form controls if you want to require all of them, and that can easily be done by using jQuery's :input selector and setting the property, like so

$(':input:not(#subnewtide)').prop('required', true)

We'll exclude the submit button, as that doesn't have to be required, obviously, not that it would matter in this case.

Then we'll listen for the input event, which covers all sorts of inputs, like typing, pasting etc, and the change event as well to cover the radio button.

Using form.checkValidity() tells us if the form is valid, and returns a boolean, so we could use it directly to set the disabled property of the submit button.

All together it looks like this, and that's all you need, a few lines of really simple code

$(':input:not(#subnewtide)').prop('required', true).on('input change', function() {
    $('#subnewtide').prop( 'disabled', !this.form.checkValidity() );
});

FIDDLE

If you have to support old browsers that don't have HTML5 validation, you can use the H5F polyfill



回答6:

Why don't you use jquery validate . It's a good plugin .

The logic works like, any change in the form it will check the form is valid or not. And also using the errorplacement function it will disable the default error message also.

$().ready(function() {
    // validate signup form on keyup and submit
    $("#contactForm").validate({
        rules: {
            title: "required",
            description: {
                required: true
            },
            newtag: {
                required: true
            },
            category: {
                required: true
            }
        },
        errorPlacement: function(error, element) {
            return true;
        },
        submitHandler: function() {


        }
    });


    $('#contactForm').change(function() {
        if ($("#contactForm").valid()) {
            $("#subnewtide").removeAttr("disabled");
        }
    });

});

Fiddle



回答7:

There's actually a pretty easy approach. I'm using native JavaScript, but I think it is applicable in jQuery as well:

var form = document.getElementById("new_tide");
form.onchange = function onChange() {
    var enable = true;
    var inputs = form.getElementsByTagName("input");
    var textareas = form.getElementsByTagName("textarea");

    for (var i in inputs) {
        enable = enable && inputs[i].value != "";
    }

    for (var i in textareas) {
        enable = enable && textareas[i].value != "";
    }

    enable = enable && textarea.value != "";
    document.getElementById("subnewtide").disabled = !enable;
}

The change event on form is always called, when any input or textarea element was changed (click in element, type, click somewhere else or lose focus).

Edit:
Regarding hidden fields, you can exclude them by surrounding the enable calculation with an if-condition:

if (!inputs[i].hidden) {
    enable = enable && inputs[i].value != "";
}

Note:
This will work in any browser (even Internet Explorer 5.5). Check on MDN:

for ..in Loop
element.getElementsByTagName()
document.getElementById()



回答8:

Thought I might chip in. Assuming as little as possible.

jQuery("input, textarea").on("keyup click", function () { // going vanilla after easy-mode attach
    var sub = document.getElementById('subnewtide');
    if (require_all(find_form(this))) {
        sub.removeAttribute('disabled');
        sub.disabled = false;
    } else {
        sub.setAttribute('disabled', 'disabled');
        sub.disabled = true;
    }
});

function concat(a, b) { // concating Array-likes produces Array
    var slice = [].slice; // not assuming Array.prototype access
    return [].concat.call(
        slice.call(a, 0),
        slice.call(b, 0)
    );
}

function find_form(e) { // shim input.form
    if (e) do {
        if (e.tagName === 'FORM') return e;
    } while (e = e.parentNode);
    return null;
}

function require_all(form, dontIgnoreHidden) { // looks at textareas & inputs (excluding buttons)
    var inp = concat(form.getElementsByTagName('input'), form.getElementsByTagName('textarea')),
        rad = {}, // not assuming Object.create
        i, j,
        has = {}.hasOwnProperty; // not assuming Object.prototype access
    for (i = 0; i < inp.length; ++i) {
        switch ((inp[i].type || '').toLowerCase()) {
            default: // treat unknown like texts
            case 'text':
                if (!inp[i].value) return false; break;
            case 'checkbox':
                if (!inp[i].checked) return false; break;
            case 'radio':
                j = inp[i].getAttribute('name');
                if (!rad[j]) rad[j] = inp[i].checked;
                break;
            case 'hidden':
                if (dontIgnoreHidden && !inp[i].value) return false; break;
            case 'button':
            case 'submit':
                break;
        }
    }
    for (j in rad) if (!has || has.call(rad, j)) // not assuming hasOwnProperty
        if (!rad[j]) return false;
    return true;
}


回答9:

Here is a quick way to accomplish that. It involves attaching a change event listener to :radio and :checkbox elements and an input event listener to other elements. These can both use a common predefined handler that will count the number of unfilled element each time each of these events fires on the appropriate element.

function checkForm() {
    //define and initialize variables
    var unfilled = 0,
        form = $(this.form);

    //disable submit button if enabled
    $(':submit', form).prop('disabled', true);

    //count number of unfilled elements
    $(':input', form).each(function() {
        if( $(this).is(':radio,:checkbox') ) {
            $('input[name=' + this.name + ']:checked').length || unfilled++;
        } else {
            $('[name=' + this.name + ']').val() || unfilled++;
        }
    });
  
    //enable submit button if no unfilled element is found
    unfilled || $(':submit', form).prop('disabled', false);
}

//set up event listeners to fire above handler
$(':text,textarea,select').on('input', checkForm);
$(':radio,:checkbox').on('change', checkForm);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<form action="#" method="post" id="new_tide">
    Title: <input id="titlenewtide" type="text" name="title" required> <br>
    Description: <textarea name="description" id="description"></textarea> <br>
    Tag:  <input id="newtag" type="text" name="newtag" required> <br>
    Category: <input type="radio" name="category" value="19" required> Animation
    <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button> 
</form>



回答10:

My solution is base on standard JavaScript.

HTML form

<form action="#" method="post" id="new_tide" name="form1">
    Title: <input onkeyup="myBtnActivator(1)" id="titlenewtide" name="title" type="text" required> <br>
    Description: <textarea onkeyup="myBtnActivator(2)" id="description" name="description"></textarea> <br>
    Tag: <input id="newtag" onkeyup="myBtnActivator(3)" name="newtag" type="text" required> <br>
    Category: <input name="category" onchange="myBtnActivator(4)" type="radio" value="19" required> Animation
    <button id="subnewtide" name="subnewtide" type="submit" value="Submit">Submit</button>
</form>

JavaScript

<script>
    document.getElementById("subnewtide").disabled = true;
    var input1 = false;
    var input2 = false;
    var input3 = false;
    var input4 = false;

    function myBtnActivator(i) {
        switch (i) {
            case 1:
                input1 = true;
                if (document.form1.title.value == "")
                    input1 = false;
                break;
            case 2:
                input2 = true;
                if (document.form1.description.value == "")
                    input2 = false;
                break;
            case 3:
                input3 = true;
                if (document.form1.newtag.value == "")
                    input3 = false;
                break;
            case 4:
                input4 = true;
                if (document.form1.subnewtide.value == "")
                    input4 = false;
                break;
        }
        trigger();
    }

    function trigger() {
        if (input1 == true && input2 == true && input3 == true && input4 == true) {
            document.getElementById("subnewtide").disabled = false;
        } else {
            document.getElementById("subnewtide").disabled = true;
        }
    }
</script>


回答11:

    var inputs = $("form#myForm input, form#myForm textarea");

    var validateInputs = function validateInputs(inputs) {
      var validForm = true;
      inputs.each(function(index) {
        var input = $(this);
        if (!input.val() || (input.type === "radio" && !input.is(':checked'))) {
          $("#subnewtide").attr("disabled", "disabled");
          validForm = false;
        }
      });
      return validForm;
    }


    inputs.each(function() {
      var input = $(this);
      if (input.type === "radio") {
        input.change(function() {
          if (validateInputs(inputs)) {
            $("#subnewtide").removeAttr("disabled");
          }
        });
      } else {
        input.keyup(function() {
          if (validateInputs(inputs)) {
            $("#subnewtide").removeAttr("disabled");
          }
        });
      }
    });
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="#" method="post" id="myForm">

  Title:
  <input id="titlenewtide" type="text" name="title" required>
  <br>Description:
  <textarea name="description" id="description"></textarea>
  <br>Tag:
  <input id="newtag" type="text" name="newtag" required>
  <br>Category:
  <input type="radio" name="category" value="19" required>Animation
  <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button>

</form>



回答12:

Use this html<br>
HTML:
<br>
<pre>
<form action="#" method="post" id="">
        Title: ##<input id="titlenewtide" type="text" name="title" required> 
        Description: <textarea name="description" id="description"></textarea>
        Tag:  <input id="newtag" type="text" name="newtag" required> 
        Category: <input type="checkbox" onclick="validate()" name="category" id="cate"value="19" required > Animation
        <button type="submit" value="Submit" name="subnewtide" id="subnewtide" disabled="disabled">Submit</button>

</form>
</pre>
validation code:<br>
//on each key up function intiate the function validate
<pre>
    jQuery("input[type='text']").on("keyup", function () {
        validate();
    });
    jQuery("#description").on("keyup", function () {
        validate();
    });

    function validate(){
     jQuery("input[type='text']").each(function(){

        if (jQuery(this).val() != "" )
        {
            if((jQuery("#description").val() !="") && (jQuery("#cate").is(':checked')))
            {

                jQuery("#subnewtide").removeAttr("disabled"); 
            }
            else {
                jQuery("#subnewtide").attr("disabled", "disabled");
            }
        } 
    });
    }
    </pre>
    you can find the fiddle in : https://jsfiddle.net/s8uv2gkp/


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