mermaid/src/editor.js

function decodeHTMLEntities (str) {
  if (str && typeof str === 'string') {
      // strip script/html tags
    var element = document.querySelector('.editor')

    str = str.replace(/<script[^>]*>([\S\s]*?)<\/script>/gmi, '')
    str = str.replace(/<\/?\w(?:[^"'>]|"[^"]*"|'[^']*')*>/gmi, '')
    element.innerHTML = str
    str = element.textContent
    element.textContent = ''
  }

  return str
}

var mermaidEditor = {
  $: document.querySelector,
  textField: '',
  submit: '',
  graph: '',

  init: function () {
    document.querySelector('.button').addEventListener('click', function () {
      mermaidEditor.update()
    })
  },

  update: function () {
    var txt = document.querySelector('.editor').value
    txt = txt.replace(/>/g, '&gt;')
    txt = txt.replace(/</g, '&lt;')
    txt = decodeHTMLEntities(txt).trim()

    document.querySelector('.mermaid').innerHTML = txt
    global.mermaid.init()
    document.querySelector('.editor').value = txt
  }
}

document.addEventListener('DOMContentLoaded', function () {
  mermaidEditor.init()
}, false)

exports = mermaidEditor