sublime-keymaps.json

[
  { "keys": ["ctrl+alt+b"], "command": "open_in_browser" },
  { "keys": ["ctrl+space"], "command": "auto_complete" },
  { "keys": ["ctrl+space"], "command": "replace_completion_with_auto_complete", "context":
    [
      { "key": "last_command", "operator": "equal", "operand": "insert_best_completion" },
      { "key": "auto_complete_visible", "operator": "equal", "operand": false },
      { "key": "setting.tab_completion", "operator": "equal", "operand": true }
    ]
  },
  {
    "keys": ["tab"],
    "command": "expand_abbreviation_by_tab",

    // put comma-separated syntax selectors for which
    // you want to expandEmmet abbreviations into "operand" key
    // instead of SCOPE_SELECTOR.
    // Examples: source.js, text.html - source | meta.group.braces.curly.js
    "context": [
      {
        "operand": "meta.group.braces.round.js, text.html",
        "operator": "equal",
        "match_all": true,
        "key": "selector"
      },

      // run only if there's no selected text
      {
        "match_all": true,
        "key": "selection_empty"
      },

      // don't work if there are active tabstops
      {
        "operator": "equal",
        "operand": false,
        "match_all": true,
        "key": "has_next_field"
      },

      // don't work if completion popup is visible and you
      // want to insert completion with Tab. If you want to
      // expand Emmet with Tab even if popup is visible --
      // remove this section
      {
        "operand": false,
        "operator": "equal",
        "match_all": true,
        "key": "auto_complete_visible"
      },
      {
        "match_all": true,
        "key": "is_abbreviation"
      }
    ]
  }
]