Tutorial: Build a Web page Spell Check client

Article
02/20/2024

In this tutorial, we'll build a Web page that allows users to query the Bing Spell Check API. The source code for this application is available on GitHub.

This tutorial shows you how to:

Make a simple query to the Bing Spell Check API.
Display query results.

Prerequisites

To follow along with the tutorial, you need a subscription key for the Bing Spell Check API. If you don't have one, you'll need:

An Azure subscription - Create one for free.
A Bing Spell Check resource.

Create a new Web page

Open a text editor. Create a new file named, for example, spellcheck.html.

Add HTML header

Add the HTML header information and begin the script section as follows.

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8"> 
    <title>Bing Spell Check</title>

<style type="text/css">
    html, body, div, p, h1, h2 {font-family: Verdana, "Lucida Sans", sans-serif;}

    html, body, div, p  {font-weight: normal;}
    h1, h2 {font-weight: bold;}
    sup {font-weight: normal;}

    html, body, div, p  {font-size: 12px;}
    h1 {font-size: 20px;}
    h2 {font-size: 16px;}
    h1, h2 {clear: left;}

    img#logo {float: right;
</style>

<script type="text/javascript">

getSubscriptionKey function

The getSubscriptionKey function returns the Bing Spell Check API key. It either retrieves it from local storage (that is, a cookie) or prompts the user for it if needed.

Begin the getSubscriptionKey function and declare the cookie name as follows.

getSubscriptionKey = function() {

    var COOKIE = "bing-spell-check-api-key";   // name used to store API key in key/value storage

The findCookie helper function returns the value of the specified cookie; if the cookie is not found, it returns an empty string.

    function findCookie(name) {
        var cookies = document.cookie.split(";");
        for (var i = 0; i < cookies.length; i++) {
            var keyvalue = cookies[i].split("=");
            if (keyvalue[0].trim() === name) {
                return keyvalue[1];
            }
        }
        return "";
        }

The getSubscriptionKeyCookie helper function prompts the user for the value of the Bing Spell Check API key, and returns the key value.

    function getSubscriptionKeyCookie() {
        var key = findCookie(COOKIE);
        while (key.length !== 32) {
            key = prompt("Enter Bing Spell Check API subscription key:", "").trim();
            var expiry = new Date();
            expiry.setFullYear(expiry.getFullYear() + 2);
            document.cookie = COOKIE + "=" + key.trim() + "; expires=" + expiry.toUTCString();
        }
        return key;
    }

The getSubscriptionKeyLocalStorage helper function first tries to retrieve the Bing Spell Check API key by looking up the appropriate cookie. If the cookie is not found, it prompts the user for the key value. It then returns the key value.

    function getSubscriptionKeyLocalStorage() {
        var key = localStorage.getItem(COOKIE) || "";
        while (key.length !== 32)
            key = prompt("Enter Bing Spell Check API subscription key:", "").trim();
        localStorage.setItem(COOKIE, key)
        return key;
    }

The getSubscriptionKey helper function takes one parameter, invalidate. If invalidate is true, getSubscriptionKey deletes the cookie that contains the Bing Spell Check API key. If invalidate is false, getSubscriptionKey returns the value of the Bing Spell Check API key.

    function getSubscriptionKey(invalidate) {
        if (invalidate) {
            try {
                localStorage.removeItem(COOKIE);
            } catch (e) {
                document.cookie = COOKIE + "=";
            }
        } else {
            try {
                return getSubscriptionKeyLocalStorage();
            } catch (e) {
                return getSubscriptionKeyCookie();
            }
        }
    }

Return the getSubscriptionKey helper function as the result of the outer getSubscriptionKey function. Close the definition of the outer getSubscriptionKey function.

    return getSubscriptionKey;

}();

Helper functions

The pre helper function returns the specified text preformatted with the pre HTML tag.

function pre(text) {
    return "<pre>" + text.replace(/&/g, "&amp;").replace(/</g, "&lt;") + "</pre>"
}

The renderSearchResults function displays the specified results from the Bing Spell Check API, using JSON pretty printing.

function renderSearchResults(results) {
    document.getElementById("results").innerHTML = pre(JSON.stringify(results, null, 2));
}

The renderErrorMessage function displays the specified error message and error code.

function renderErrorMessage(message, code) {
    if (code)
        document.getElementById("results").innerHTML = "<pre>Status " + code + ": " + message + "</pre>";
    else
        document.getElementById("results").innerHTML = "<pre>" + message + "</pre>";
}

bingSpellCheck function

The bingSpellCheck function is called each time the user enters text in the HTML form field. It takes two parameters: the contents of the HTML form field, and the Bing Spell Check API key.

function bingSpellCheck(query, key) {

Specify the Bing Spell Check API endpoint and declare an XMLHttpRequest object, which we will use to send requests to the endpoint.

    var endpoint = "https://api.bing.microsoft.com/v7.0/spellcheck/";

    var request = new XMLHttpRequest();

    try {
        request.open("GET", endpoint + "?mode=proof&mkt=en-US&text=" + encodeURIComponent(query));
    }
    catch (e) {
        renderErrorMessage("Bad request");
        return false;
    }

Set the Ocp-Apim-Subscription-Key header to the value of the Bing Spell Check API key.

    request.setRequestHeader("Ocp-Apim-Subscription-Key", key);

Handle the response from the endpoint. If the status is 200 (OK), display the results; otherwise, display the error information.

    request.addEventListener("load", function() {
        if (this.status === 200) {
            renderSearchResults(JSON.parse(this.responseText));
        }
        else {
            if (this.status === 401) getSubscriptionKey(true);
            renderErrorMessage(this.statusText, this.status);
        }
    });

Also handle possible error events from the XMLHttpRequest object.

    request.addEventListener("error", function() {
        renderErrorMessage("Network error");
    });

    request.addEventListener("abort", function() {
        renderErrorMessage("Request aborted");
    });

Send the request. Close the bingSpellCheck function, the script tag, and the head tag.

    request.send();
    return false;
}
// --></script>

</head>

HTML body

When the Web page loads, make sure we have the Bing Spell Check API key, prompting the user for it if needed.

<body onload="document.forms.bing.query.focus(); getSubscriptionKey();">

Display the Bing logo.

<img id="logo" align=base src="data:image/png;base64,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">

Create an HTML form with a text field. Handle the onsubmit event and call the bingSpellCheck function, passing the contents of the text field and the Bing Spell Check API key.

<form name="bing" onsubmit="return bingSpellCheck(this.query.value, getSubscriptionKey())">
    <h2>Spell Check</h2>
    <input type="text" name="query" size="80" placeholder="Spell Check" autocomplete=off>
</form>

Add the HTML div tag that we use to display the results. The JavaScript we defined previously refers to this div tag.

<h2>Results</h2>
<div id="results">
<p>None yet.</p>

</div>

</body>
</html>

Save the file.

Display results

Open the Web page in your browser. At the prompt, enter your Bing Spell Check API subscription key. Enter a query (for example, "Hollo, wlrd!") in the Spell Check text box and press Enter. The Web page then displays the query results.

{
  "_type": "SpellCheck",
  "flaggedTokens": [
    {
      "offset": 0,
      "token": "Hollo",
      "type": "UnknownToken",
      "suggestions": [
        {
          "suggestion": "Hello",
          "score": 0.856629936217145
        },
        {
          "suggestion": "Hollow",
          "score": 0.816717853225633
        }
      ]
    },
    {
      "offset": 7,
      "token": "wlrd",
      "type": "UnknownToken",
      "suggestions": [
        {
          "suggestion": "world",
          "score": 0.856629936217145
        }
      ]
    }
  ]
}

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