What is the method for altering the background color of an input field upon entering text?

Question

What is the method for altering the background color of an input field upon entering text?

As a beginner in Javascript and jQuery, I am struggling to understand why my code is behaving the way it does.

I have written two similar functions aimed at changing the background color of an input field. The objective is to set the background color of the input field to #00FF7F when something is typed into the field. If nothing is typed, the background should be transparent.

Javascript Code:


$(document).ready(function () {
    var $input1 = $("#logindata1");
    var $input2 = $("#logindata2");

    function onChangeInput1() {
        $input1.css("background-color", "#00FF7F");
        var value = $.trim($(".form-control").val());

        if (value.length === 0) {
            $input1.css("background-color", "transparent");
        }
    }

    function onChangeInput2() {
        $input2.css("background-color", "#00FF7F");
        var value = $.trim($(".form-control").val());

        if (value.length === 0) {
            $input2.css("#background-color", "transparent");
        }
    }

    $input1.on("keyup", onChangeInput1);
    $input2.on("keyup", onChangeInput2);       
});

CSS:


#loginbox {
    width: 400px;
    height: 200px;
    margin-left: auto;
    margin-right: auto;
    margin-top: 25%;
}

.logindata {
    margin-left: auto;
    margin-right: auto;
    margin-top: 20px;
    height: 60px;
    width: 290px;
    transition: 0.25s ease;
}

.form-control {
    margin-left: auto;
    margin-right: auto;
    height: 55px;
    width: 288px;
    border-style: none;
    background-color: transparent;
    text-align: center;
    border: solid 2px #00FF7F;
    transition: 0.25s ease;
    font-size: 25px;
    font-family: "Trebuchet MS";
}

... (additional CSS properties)

Simple HTML:

<!DOCTYPE html>
(HTML code)

To see how the Username and Password fields react differently, try typing into both on the provided jsbin link.

You can view images showing the different reactions by following this link: https://i.sstatic.net/RFHs1.jpg

I believe there might be a more efficient way to streamline my javascript/jQuery code using a single function that each input field calls, rather than having a separate function for each.

javascript jquery html css

Answer 1

Answer №1

For situations where both fields are mandatory, a straightforward CSS-only solution is available.

To ensure that the <input> tags are required, simply add the attribute required, followed by utilizing the pseudo-class :valid.

.form-control:valid {
  background-color: #00FF7F;
}

Here is the code snippet:

#loginbox {
  width: 400px;
  height: 200px;
  margin-left: auto;
  margin-right: auto;
  margin-top: 25%;
}
.logindata {
  margin-left: auto;
  margin-right: auto;
  margin-top: 20px;
  height: 60px;
  width: 290px;
  transition: 0.25s ease;
}
.form-control {
  margin-left: auto;
  margin-right: auto;
  height: 55px;
  width: 288px;
  border-style: none;
  background-color: transparent;
  text-align: center;
  border: solid 2px #00FF7F;
  transition: 0.25s ease;
  font-size: 25px;
  font-family: "Trebuchet MS";
}
.form-control:hover {
  box-shadow: 0px 0px 30px #2E8B57;
}
::-webkit-input-placeholder {
  color: #00FF7F;
}
.form-control:valid {
  background-color: #00FF7F;
}

<div id="loginbox">
  <div class="logindata" id="logindata1">
    <input type="text" class="form-control" placeholder="Username" required>
  </div>

  <div class="logindata" id="logindata2">
    <input type="password" class="form-control" placeholder="Password" required>
  </div>
</div>

Answer 2

For situations where both fields are mandatory, a straightforward CSS-only solution is available.

To ensure that the <input> tags are required, simply add the attribute required, followed by utilizing the pseudo-class :valid.

.form-control:valid {
  background-color: #00FF7F;
}

Here is the code snippet:

#loginbox {
  width: 400px;
  height: 200px;
  margin-left: auto;
  margin-right: auto;
  margin-top: 25%;
}
.logindata {
  margin-left: auto;
  margin-right: auto;
  margin-top: 20px;
  height: 60px;
  width: 290px;
  transition: 0.25s ease;
}
.form-control {
  margin-left: auto;
  margin-right: auto;
  height: 55px;
  width: 288px;
  border-style: none;
  background-color: transparent;
  text-align: center;
  border: solid 2px #00FF7F;
  transition: 0.25s ease;
  font-size: 25px;
  font-family: "Trebuchet MS";
}
.form-control:hover {
  box-shadow: 0px 0px 30px #2E8B57;
}
::-webkit-input-placeholder {
  color: #00FF7F;
}
.form-control:valid {
  background-color: #00FF7F;
}

<div id="loginbox">
  <div class="logindata" id="logindata1">
    <input type="text" class="form-control" placeholder="Username" required>
  </div>

  <div class="logindata" id="logindata2">
    <input type="password" class="form-control" placeholder="Password" required>
  </div>
</div>

Answer 3

Answer №2

View the code on jsFiddle: here

Using jQuery:

$(document).ready(function() {
 $('.change-background').on('change', function() {
    var $this = $(this);
    var value = $.trim($this.val());

    // ToggleClass can add or remove class based on condition
    $this.toggleClass('filled-background', value.length !== 0);
  }).change();
});

Rather than using the keyup event, simply listen for the change event to change the background color of inputs with the class change-background.

Html snippet:

<div id="loginbox">
  <div class="logindata" id="logindata1">
    <input type="text" class="change-background form-control" placeholder="Username">
  </div>

  <div class="logindata" id="logindata2">
    <input type="password" class="change-background form-control" placeholder="Password">
  </div>
</div>

Css (background color)

.filled-background {
  background-color: #00FF7F;
}

Additional Note

Consider users who may paste their credentials instead of typing, as it may not trigger the keyup event.

Answer 4

View the code on jsFiddle: here

Using jQuery:

$(document).ready(function() {
 $('.change-background').on('change', function() {
    var $this = $(this);
    var value = $.trim($this.val());

    // ToggleClass can add or remove class based on condition
    $this.toggleClass('filled-background', value.length !== 0);
  }).change();
});

Rather than using the keyup event, simply listen for the change event to change the background color of inputs with the class change-background.

Html snippet:

<div id="loginbox">
  <div class="logindata" id="logindata1">
    <input type="text" class="change-background form-control" placeholder="Username">
  </div>

  <div class="logindata" id="logindata2">
    <input type="password" class="change-background form-control" placeholder="Password">
  </div>
</div>

Css (background color)

.filled-background {
  background-color: #00FF7F;
}

Additional Note

Consider users who may paste their credentials instead of typing, as it may not trigger the keyup event.

Answer 5

Answer №3

Your code has a function that clears the background color when the length is 0. It uses the following snippet to check the length:

var value = $.trim($(".form-control").val());

The issue lies in the selector $(".form-control") because it selects all elements with the CSS class of .form-control, but there could be more than one element with this class, resulting in always getting the value from the first element found.

To solve this problem, you should modify the code to search for the specific control by its ID, like this:

var value = $.trim($("#logindata1 input").val()); //get user ID
var value = $.trim($("#logindata2 input").val()); //get password

Answer 6

Your code has a function that clears the background color when the length is 0. It uses the following snippet to check the length:

var value = $.trim($(".form-control").val());

The issue lies in the selector $(".form-control") because it selects all elements with the CSS class of .form-control, but there could be more than one element with this class, resulting in always getting the value from the first element found.

To solve this problem, you should modify the code to search for the specific control by its ID, like this:

var value = $.trim($("#logindata1 input").val()); //get user ID
var value = $.trim($("#logindata2 input").val()); //get password

Answer 7

Answer №4

You have a few minor errors, but don't worry. We can easily correct them.

Issue Number One

Other responses have pointed out an important detail: you are attempting to retrieve the value by selecting all elements with the class form-control.

var value = $.trim($(".form-control").val());

To fix this, you can use your previously declared variables $input1 and $input2 for selecting the values like this:

var value = $.trim($input1.val());
var value = $.trim($input2.val());

Second Problem

Alright, the first problem is resolved. Now onto the second issue in your second function where you're trying to set an invalid CSS property:

$input2.css("#background-color", "transparent");

The correct syntax should be:

$input2.css("background-color", "transparent");

(without the #).

Moving On

Great progress so far. The IDs you've assigned as logindata1 and logindata2 belong to your div elements. Therefore, you're mistakenly attempting to retrieve the value of the div rather than the input. You can correct this by appending input to your selector, like this:

var $input1 = $("#logindata1 input");
var $input2 = $("#logindata2 input");

Final Touches

So, everything should come together nicely now:

$(document).ready(function () {
    var $input1 = $("#logindata1 input");
    var $input2 = $("#logindata2 input");

    function onChangeInput1() {

        $input1.css("background-color", "#00007F");
        var value = $.trim($input1.val());

        if (value.length === 0) {
            $input1.css("background-color", "transparent");
        }
    }

    function onChangeInput2() {
        $input2.css("background-color", "#00007F");
        var value = $.trim($input2.val());

        if (value.length === 0) {
            $input2.css("background-color", "transparent");
        }
    }

    $input1.on("keyup", onChangeInput1);
    $input2.on("keyup", onChangeInput2);
});

Answer 8

You have a few minor errors, but don't worry. We can easily correct them.

Issue Number One

Other responses have pointed out an important detail: you are attempting to retrieve the value by selecting all elements with the class form-control.

var value = $.trim($(".form-control").val());

To fix this, you can use your previously declared variables $input1 and $input2 for selecting the values like this:

var value = $.trim($input1.val());
var value = $.trim($input2.val());

Second Problem

Alright, the first problem is resolved. Now onto the second issue in your second function where you're trying to set an invalid CSS property:

$input2.css("#background-color", "transparent");

The correct syntax should be:

$input2.css("background-color", "transparent");

(without the #).

Moving On

Great progress so far. The IDs you've assigned as logindata1 and logindata2 belong to your div elements. Therefore, you're mistakenly attempting to retrieve the value of the div rather than the input. You can correct this by appending input to your selector, like this:

var $input1 = $("#logindata1 input");
var $input2 = $("#logindata2 input");

Final Touches

So, everything should come together nicely now:

$(document).ready(function () {
    var $input1 = $("#logindata1 input");
    var $input2 = $("#logindata2 input");

    function onChangeInput1() {

        $input1.css("background-color", "#00007F");
        var value = $.trim($input1.val());

        if (value.length === 0) {
            $input1.css("background-color", "transparent");
        }
    }

    function onChangeInput2() {
        $input2.css("background-color", "#00007F");
        var value = $.trim($input2.val());

        if (value.length === 0) {
            $input2.css("background-color", "transparent");
        }
    }

    $input1.on("keyup", onChangeInput1);
    $input2.on("keyup", onChangeInput2);
});

Answer 9

Answer №5

Your validation method needs adjustment. Instead of checking both inputs every time with your jQuery code, focus on checking the individual inputs separately.

Modify your approach by targeting and validating the specific inputs that you are concerned about.

$(document).ready(function () {
    var $input1 = $("#logindata1");
    var $input2 = $("#logindata2");

    function onChangeInput1() {
        $input1.css("background-color", "#00FF7F");
        var value = $.trim($input1.val());

        if (value.length === 0) {
            $input1.css("background-color", "transparent");
        }
    }

    function onChangeInput2() {
        $input2.css("background-color", "#00FF7F");
        var value = $.trim($input2.val());

        if (value.length === 0) {
            $input2.css("#background-color", "transparent");
        }
    }

    $input1.on("keyup", onChangeInput1);
    $input2.on("keyup", onChangeInput2);       
});

Answer 10

Your validation method needs adjustment. Instead of checking both inputs every time with your jQuery code, focus on checking the individual inputs separately.

Modify your approach by targeting and validating the specific inputs that you are concerned about.

$(document).ready(function () {
    var $input1 = $("#logindata1");
    var $input2 = $("#logindata2");

    function onChangeInput1() {
        $input1.css("background-color", "#00FF7F");
        var value = $.trim($input1.val());

        if (value.length === 0) {
            $input1.css("background-color", "transparent");
        }
    }

    function onChangeInput2() {
        $input2.css("background-color", "#00FF7F");
        var value = $.trim($input2.val());

        if (value.length === 0) {
            $input2.css("#background-color", "transparent");
        }
    }

    $input1.on("keyup", onChangeInput1);
    $input2.on("keyup", onChangeInput2);       
});

What is the method for altering the background color of an input field upon entering text?

Answer №1

Answer №2

Additional Note

Answer №3

Answer №4

Issue Number One

Second Problem

Moving On

Final Touches

Answer №5

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