CSS Input with width: 100% goes outside parent's bound

216
votes

I am trying to make a login form constituted of two input fields with an inset padding, but those two fields always end up exceeding its parent's boundaries; the issue stems from the added inset padding. What could be done in order to rectify this issue?

JSFiddle snippet: http://jsfiddle.net/4x2KP/

N.B.: The code may not be at its cleanest. For instance, the span element that encapsulates the text inputs may not be needed at all.

    #mainContainer {
    	line-height: 20px;
    	font-family: "Helvetica Neue",Helvetica,Arial,sans-serif;
        background-color: rgba(0,50,94,0.2);
    	margin: 20px auto;
    	display: table;
    	-moz-border-radius: 15px;
    	border-style: solid;
    	border-color: rgb(40, 40, 40);
    	border-radius: 2px 5px 2px 5px / 5px 2px 5px 2px;
    	border-radius: 2px;
    	border-radius: 2px 5px / 5px;
    	box-shadow: 0 5px 10px 5px rgba(0,0,0,0.2);
    }
    
    .loginForm {
    	width: 320px;
    	height: 250px;
    	padding: 10px 15px 25px 15px;
    	overflow: hidden;
    }
    
    .login-fields > .login-bottom input#login-button_normal {
    	float: right;
    	padding: 2px 25px;
    	cursor: pointer;
    	margin-left: 10px;
    }
    
    .login-fields > .login-bottom input#login-remember {
    	float: left;
    	margin-right: 3px;
    }
    
    .spacer {
    	padding-bottom: 10px;
    }
    
    /* ELEMENT OF INTEREST HERE! */
    input[type=text],
    input[type=password] {
        width: 100%;
    	height: 20px;
    	padding: 5px 10px;
    	background-color: rgb(215, 215, 215);
        line-height: 20px;
        font-size: 12px;
        color: rgb(136, 136, 136);
        border-radius: 2px 2px 2px 2px;
        border: 1px solid rgb(114, 114, 114);
    	box-shadow: 0 1px 0 rgba(24, 24, 24,0.1);
    }
    
    input[type=text]:hover,
    input[type=password]:hover,
    label:hover ~ input[type=text],
    label:hover ~ input[type=password] {
     	background:rgb(242, 242, 242) !important;
    }
    
    input[type=submit]:hover {
      box-shadow:
        inset 0 1px 0 rgba(255,255,255,0.3),
        inset 0 -10px 10px rgba(255,255,255,0.1);
    }
    <div id="mainContainer">
        <div id="login" class="loginForm">
            <div class="login-top">
            </div>
            <form class="login-fields" onsubmit="alert('test'); return false;">
                <div id="login-email" class="login-field">
                    <label for="email" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">E-mail address</label>
                    <span><input name="email" id="email" type="text"></input></span>
                </div>
                <div class="spacer"></div>
                <div id="login-password" class="login-field">
                    <label for="password" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">Password</label>
                    <span><input name="password" id="password" type="password"></input></span>
                </div>
                <div class="login-bottom">
                    <input type="checkbox" name="remember" id="login-remember"></input>
                    <label for="login-remember" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">Remember my email</label>
                    <input type="submit" name="login-button" id="login-button_normal" style="cursor: pointer" value="Log in"></input>
                </div>
            </form>
        </div>
    </div>
10
cssformsinputwidth

10 Answers

377
votes

According to the CSS basic box model, an element's width and height are applied to its content box. Padding falls outside of that content box and increases the element's overall size.

As a result, if you set an element with padding to 100% width, its padding will make it wider than 100% of its containing element. In your context, inputs become wider than their parent.

CSS Basic Box Model

You can change the way the box model treats padding and width. Set the box-sizing CSS property to border-box to prevent padding from affecting an element's width or height:

border-box : The width and height properties include the padding and border, but not the margin... Note that padding and border will be inside of the box.

Note the browser compatibility of box-sizing (IE8+).
At the time of this edit, no prefixes are necessary.

Paul Irish and Chris Coyier recommend the "inherited" usage below:

html {
  box-sizing: border-box;
}
*, *:before, *:after {
  box-sizing: inherit;
}

For reference, see:
* { Box-sizing: Border-box } FTW
Inheriting box-sizing Probably Slightly Better Best-Practice.

Here's a demonstration in your specific context:

#mainContainer {
  line-height: 20px;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  background-color: rgba(0, 50, 94, 0.2);
  margin: 20px auto;
  display: table;
  -moz-border-radius: 15px;
  border-style: solid;
  border-color: rgb(40, 40, 40);
  border-radius: 2px 5px 2px 5px / 5px 2px 5px 2px;
  border-radius: 2px;
  border-radius: 2px 5px / 5px;
  box-shadow: 0 5px 10px 5px rgba(0, 0, 0, 0.2);
}
.loginForm {
  width: 320px;
  height: 250px;
  padding: 10px 15px 25px 15px;
  overflow: hidden;
}
.login-fields > .login-bottom input#login-button_normal {
  float: right;
  padding: 2px 25px;
  cursor: pointer;
  margin-left: 10px;
}
.login-fields > .login-bottom input#login-remember {
  float: left;
  margin-right: 3px;
}
.spacer {
  padding-bottom: 10px;
}
input[type=text],
input[type=password] {
  width: 100%;
  height: 30px;
  padding: 5px 10px;
  background-color: rgb(215, 215, 215);
  line-height: 20px;
  font-size: 12px;
  color: rgb(136, 136, 136);
  border-radius: 2px 2px 2px 2px;
  border: 1px solid rgb(114, 114, 114);
  box-shadow: 0 1px 0 rgba(24, 24, 24, 0.1);
  box-sizing: border-box;
}
input[type=text]:hover,
input[type=password]:hover,
label:hover ~ input[type=text],
label:hover ~ input[type=password] {
  background: rgb(242, 242, 242);
  !important;
}
input[type=submit]:hover {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.3), inset 0 -10px 10px rgba(255, 255, 255, 0.1);
}
.login-top {
  height: auto;/*85px;*/
}
.login-bottom {
  padding: 35px 15px 0 0;
}
<div id="mainContainer">
  <div id="login" class="loginForm">
    <div class="login-top">
    </div>
    <form class="login-fields" onsubmit="alert('test'); return false;">
      <div id="login-email" class="login-field">
        <label for="email" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">E-mail address</label>
        <span><input name="email" id="email" type="text" /></span>
      </div>
      <div class="spacer"></div>
      <div id="login-password" class="login-field">
        <label for="password" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">Password</label>
        <span><input name="password" id="password" type="password" /></span>
      </div>
      <div class="login-bottom">
        <input type="checkbox" name="remember" id="login-remember" />
        <label for="login-remember" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">Remember my email</label>
        <input type="submit" name="login-button" id="login-button_normal" style="cursor: pointer" value="Log in" />
      </div>
    </form>
  </div>
</div>

Alternatively, rather than adding padding to the <input> elements themselves, style the <span> elements wrapping the inputs. That way, the <input> elements can be set to width:100% without being affected by any additional padding. Example below:

#login-form {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  background-color: rgba(0, 50, 94, 0.2);
  margin: 20px auto;
  padding: 10px 15px 25px 15px;
  border: 4px solid rgb(40, 40, 40);
  box-shadow: 0 5px 10px 5px rgba(0, 0, 0, 0.2);
  border-radius: 2px;
  width: 320px;
}
label span {
  display: block;
  padding: .3em 1em;
  background-color: rgb(215, 215, 215);
  border-radius: .25em;
  border: 1px solid rgb(114, 114, 114);
  box-shadow: 0 1px 0 rgba(24, 24, 24, 0.1);
  margin: 0 0 1em;
}
label span:hover {
  background: rgb(242, 242, 242);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.3), inset 0 -10px 10px rgba(255, 255, 255, 0.1);
}
input[type=text],
input[type=password] {
  background: none;
  border: none;
  width: 100%;
  height: 2em;
  line-height: 2em;
  font-size: 12px;
  color: rgb(136, 136, 136);
  outline: none;
}
.login-bottom {
  margin: 2em 1em 0 0;
}
input#login-button {
  float: right;
  padding: 2px 25px;
}
input#login-remember {
  float: left;
  margin-right: 3px;
}
<form id="login-form">
  <label>E-mail address
    <span><input name="email" type="text" /></span>
  </label>
  <label>Password
    <span><input name="password" type="password" /></span>
  </label>
  <div class="login-bottom">
    <label>
      <input type="checkbox" name="remember" id="login-remember" />Remember my email
    </label>
    <input type="submit" name="login-button" id="login-button" value="Log in" />
  </div>
</form>
21
votes

If all above fail, try setting the following properties for your input, to have it take max space but not overflow:

input {
    min-width: 100%;
    max-width: 100%;
}
18
votes

The other answers seem to tell you to hard-code the width or use a browser-specific hack. I think there is a simpler way.

By calculating the width and subtracting the padding (which causes the field overlap). The 20px comes from 10px for left padding and 10px for right padding.

input[type=text],
input[type=password] {
    ...
    width: calc(100% - 20px);
}
10
votes

Try changing the box-sizing to border-box. The padding is adding to width of your input elements.

See Demo here

CSS

input[type=text],
input[type=password] {
    width: 100%;
    margin-top: 5px;
    height: 25px;
    ...
}

input {
    box-sizing: border-box;
}

+box-sizing

3
votes

Padding is added to the overall width. Because your container has a pixel width, you are better off giving the inputs a pixel width too, but remember to remove the padding and border from the width you set to avoid the same issue.

1
votes

I tried these solutions but never got a conclusive result. In the end I used proper semantic markup with a fieldset. It saved having to add any width calculations and any box-sizing.

It also allows you to set the form width as you require and the inputs remain within the padding you need for your edges.

In this example I have put a border on the form and fieldset and an opaque background on the legend and fieldset so you can see how they overlap and sit with each other.

<html>
  <head>
  <style>
    form {
      width: 300px;
      margin: 0 auto;
      border: 1px solid;
    }
    fieldset {
      border: 0;
      margin: 0;
      padding: 0 20px 10px;
      border: 1px solid blue;
      background: rgba(0,0,0,.2);
    }
    legend {
      background: rgba(0,0,0,.2);
      width: 100%;
      margin: 0 -20px;
      padding: 2px 20px;
      color: $col1;
      border: 0;
    }
    input[type="email"],
    input[type="password"],
    button {
      width: 100%;
      margin: 0 0 10px;
      padding: 0 10px;
    }
    input[type="email"],
    input[type="password"] {
      line-height: 22px;
      font-size: 16px;
    }
    button {
    line-height: 26px;
    font-size: 20px;
    }
  </style>
  </head>
  <body>
  <form>
      <fieldset>
          <legend>Log in</legend>
          <p>You may need some content here, a message?</p>
          <input type="email" id="email" name="email" placeholder="Email" value=""/>
          <input type="password" id="password" name="password" placeholder="password" value=""/>
          <button type="submit">Login</button>
      </fieldset>
  </form>
  </body>
</html>
0
votes

Padding is essentially added to the width, therefore when you say width:100% and padding: 5px 10px you're actually adding 20px to the 100% width.

0
votes

You also have an error in your css with the exclamation point in this line:

background:rgb(242, 242, 242);!important;

remove the semi-colon before it. However, !important should be used rarely and can largely be avoided.

0
votes

try code this

*, ::after, ::before {
  box-sizing: border-box;
}
-2
votes

Do you want the input fields to be centered? A trick to center elements: specify the width of the element and set the margin to auto, eg:

margin : 0px auto;
width:300px

A link to your updated fiddle:

http://jsfiddle.net/4x2KP/5/