element/examples/docs/en-US/message-box.md

MessageBox

A set of modal boxes simulating system message box, mainly for alerting information, confirm operations and prompting messages. :::tip By design MessageBox provides simulations of system's alert, confirm and prompt，so it's content should be simple. For more complicated contents, please use Dialog. :::

Alert

Alert interrupts user operation until the user confirms.

:::demo Open an alert by calling the $alert method. It simulates the system's alert, and cannot be closed by pressing ESC or clicking outside the box. In this example, two parameters message and title are received. It is worth mentioning that when the box is closed, it returns a Promise object for further processing. If you are not sure if your target browsers support Promise, you should import a third party polyfill or use callbacks instead like this example.

<template>
  <el-button type="text" @click="open">Click to open the Message Box</el-button>
</template>

<script>
  export default {
    methods: {
      open() {
        this.$alert('This is a message', 'Title', {
          confirmButtonText: 'OK',
          callback: action => {
            this.$message({
              type: 'info',
              message: `action: ${ action }`
            });
          }
        });
      }
    }
  }
</script>

:::

Confirm

Confirm is used to ask users' confirmation.

:::demo Call $confirm method to open a confirm, and it simulates the system's confirm. We can also highly customize Message Box by passing a third attribute options which is a literal object. The attribute type indicates the message type, and it's value can be success, error, info and warning. Note that the second attribute title must be a string, and if it is an object, it will be handled as the attribute options. Here we use Promise to handle further processing.

<template>
  <el-button type="text" @click="open">Click to open the Message Box</el-button>
</template>

<script>
  export default {
    methods: {
      open() {
        this.$confirm('This will permanently delete the file. Continue?', 'Warning', {
          confirmButtonText: 'OK',
          cancelButtonText: 'Cancel',
          type: 'warning'
        }).then(() => {
          this.$message({
            type: 'success',
            message: 'Delete completed'
          });
        }).catch(() => {
          this.$message({
            type: 'info',
            message: 'Delete canceled'
          });          
        });
      }
    }
  }
</script>

:::

Prompt

Prompt is used when user input is required.

:::demo Call $prompt method to open a prompt, and it simulates the system's prompt. You can use inputPattern parameter to specify your own RegExp pattern. Use inputValidator to specify validation method, and it should return Boolean or String. Returning false or String means the validation has failed, and the string returned will be used as the inputErrorMessage. In addition, you can customize the placeholder of the input box with inputPlaceholder parameter.

<template>
  <el-button type="text" @click="open">Click to open Message Box</el-button>
</template>

<script>
  export default {
    methods: {
      open() {
        this.$prompt('Please input your e-mail', 'Tip', {
          confirmButtonText: 'OK',
          cancelButtonText: 'Cancel',
          inputPattern: /[\w!#$%&'*+/=?^_`{|}~-]+(?:\.[\w!#$%&'*+/=?^_`{|}~-]+)*@(?:[\w](?:[\w-]*[\w])?\.)+[\w](?:[\w-]*[\w])?/,
          inputErrorMessage: 'Invalid Email'
        }).then(({ value }) => {
          this.$message({
            type: 'success',
            message: 'Your email is:' + value
          });
        }).catch(() => {
          this.$message({
            type: 'info',
            message: 'Input canceled'
          });       
        });
      }
    }
  }
</script>

:::

Customization

Can be customized to show various content.

:::demo The three methods mentioned above are repackagings of the $msgbox method. This example calls $msgbox method directly using the showCancelButton attribute, which is used to indicate if a cancel button is displayed. Besides we can use cancelButtonClass to add a custom style and cancelButtonText to customize the button text (the confirm button also has these fields, and a complete list of fields can be found at the end of this documentation). This example also uses the beforeClose attribute. It is a method and will be triggered when the MessageBox instance will be closed, and its execution will stop the instance from closing. It has three parameters: action, instance and done. Using it enables you to manipulate the instance before it closes, e.g. activating loading for confirm button; you can invoke the done method to close the MessageBox instance (if done is not called inside beforeClose, the instance will not be closed).

<template>
  <el-button type="text" @click="open">Click to open Message Box</el-button>
</template>

<script>
  export default {
    methods: {
      open() {
        const h = this.$createElement;
        this.$msgbox({
          title: 'Message',
          message: h('p', null, [
            h('span', null, 'Message can be '),
            h('i', { style: 'color: teal' }, 'VNode')
          ]),
          showCancelButton: true,
          confirmButtonText: 'OK',
          cancelButtonText: 'Cancel',
          beforeClose: (action, instance, done) => {
            if (action === 'confirm') {
              instance.confirmButtonLoading = true;
              instance.confirmButtonText = 'Loading...';
              setTimeout(() => {
                done();
                setTimeout(() => {
                  instance.confirmButtonLoading = false;
                }, 300);
              }, 3000);
            } else {
              done();
            }
          }
        }).then(action => {
          this.$message({
            type: 'info',
            message: 'action: ' + action
          });
        });
      },
    }
  }
</script>

:::

:::tip The content of MessageBox can be VNode, allowing us to pass custom components. When opening the MessageBox, Vue compares new VNode with old VNode, then figures out how to efficiently update the UI, so the components may not be completely re-rendered (#8931). In this case, you can add a unique key to VNode each time MessageBox opens: example. :::

Use HTML String

message supports HTML string.

:::demo Set dangerouslyUseHTMLString to true and message will be treated as an HTML string.

<template>
  <el-button type="text" @click="open">Click to open Message Box</el-button>
</template>

<script>
  export default {
    methods: {
      open() {
        this.$alert('<strong>This is <i>HTML</i> string</strong>', 'HTML String', {
          dangerouslyUseHTMLString: true
        });
      }
    }
  }
</script>

:::

:::warning Although message property supports HTML strings, dynamically rendering arbitrary HTML on your website can be very dangerous because it can easily lead to XSS attacks. So when dangerouslyUseHTMLString is on, please make sure the content of message is trusted, and never assign message to user-provided content. :::

Distinguishing cancel and close

In some cases, clicking the cancel button and close button may have different meanings.

:::demo By default, the parameters of Promise's reject callback and callback are 'cancel' when the user cancels (clicking the cancel button) and closes (clicking the close button or mask layer, pressing the ESC key) the MessageBox. If distinguishCancelAndClose is set to true, the parameters of the above two operations are 'cancel' and 'close' respectively.

<template>
  <el-button type="text" @click="open">Click to open Message Box</el-button>
</template>

<script>
  export default {
    methods: {
      open() {
        this.$confirm('You have unsaved changes, save and proceed?', 'Confirm', {
          distinguishCancelAndClose: true,
          confirmButtonText: 'Save',
          cancelButtonText: 'Discard Changes'
        })
          .then(() => {
            this.$message({
              type: 'info',
              message: 'Changes saved. Proceeding to a new route.'
            });
          })
          .catch(action => {
            this.$message({
              type: 'info',
              message: action === 'cancel'
                ? 'Changes discarded. Proceeding to a new route.'
                : 'Stay in the current route'
            })
          });
      }
    }
  }
</script>

:::

Centered content

Content of MessageBox can be centered.

:::demo Setting center to true will center the content

<template>
  <el-button type="text" @click="open">Click to open Message Box</el-button>
</template>

<script>
  export default {
    methods: {
      open() {
        this.$confirm('This will permanently delete the file. Continue?', 'Warning', {
          confirmButtonText: 'OK',
          cancelButtonText: 'Cancel',
          type: 'warning',
          center: true
        }).then(() => {
          this.$message({
            type: 'success',
            message: 'Delete completed'
          });
        }).catch(() => {
          this.$message({
            type: 'info',
            message: 'Delete canceled'
          });
        });
      }
    }
  }
</script>

:::

Global method

If Element is fully imported, it will add the following global methods for Vue.prototype: $msgbox, $alert, $confirm and $prompt. So in a Vue instance you can call MessageBox like what we did in this page. The parameters are:

• $msgbox(options)
• $alert(message, title, options) or $alert(message, options)
• $confirm(message, title, options) or $confirm(message, options)
• $prompt(message, title, options) or $prompt(message, options)

Local import

If you prefer importing MessageBox on demand:

import { MessageBox } from 'element-ui';

The corresponding methods are: MessageBox, MessageBox.alert, MessageBox.confirm and MessageBox.prompt. The parameters are the same as above.

Options

Attribute	Description	Type	Accepted Values	Default
title	title of the MessageBox	string	—	—
message	content of the MessageBox	string	—	—
dangerouslyUseHTMLString	whether message is treated as HTML string	boolean	—	false
type	message type, used for icon display	string	success / info / warning / error	—
iconClass	custom icon's class, overrides type	string	—	—
customClass	custom class name for MessageBox	string	—	—
callback	MessageBox closing callback if you don't prefer Promise	function(action), where action can be 'confirm', 'cancel' or 'close', and instance is the MessageBox instance. You can access to that instance's attributes and methods	—	—
showClose	whether to show close icon of MessageBox	boolean	—	true
beforeClose	callback before MessageBox closes, and it will prevent MessageBox from closing	function(action, instance, done), where action can be 'confirm', 'cancel' or 'close'; instance is the MessageBox instance, and you can access to that instance's attributes and methods; done is for closing the instance	—	—
distinguishCancelAndClose	whether to distinguish canceling and closing the MessageBox	boolean	—	false
lockScroll	whether to lock body scroll when MessageBox prompts	boolean	—	true
showCancelButton	whether to show a cancel button	boolean	—	false (true when called with confirm and prompt)
showConfirmButton	whether to show a confirm button	boolean	—	true
cancelButtonText	text content of cancel button	string	—	Cancel
confirmButtonText	text content of confirm button	string	—	OK
cancelButtonClass	custom class name of cancel button	string	—	—
confirmButtonClass	custom class name of confirm button	string	—	—
closeOnClickModal	whether MessageBox can be closed by clicking the mask	boolean	—	true (false when called with alert)
closeOnPressEscape	whether MessageBox can be closed by pressing the ESC	boolean	—	true (false when called with alert)
closeOnHashChange	whether to close MessageBox when hash changes	boolean	—	true
showInput	whether to show an input	boolean	—	false (true when called with prompt)
inputPlaceholder	placeholder of input	string	—	—
inputType	type of input	string	—	text
inputValue	initial value of input	string	—	—
inputPattern	regexp for the input	regexp	—	—
inputValidator	validation function for the input. Should returns a boolean or string. If a string is returned, it will be assigned to inputErrorMessage	function	—	—
inputErrorMessage	error message when validation fails	string	—	Illegal input
center	whether to align the content in center	boolean	—	false
roundButton	whether to use round button	boolean	—	false