Internet provides us a lot of services which we can access through the respective websites. Many of times, we are need to search information on a particular topic. To perform search on Internet, we can make of search engine like Google, Yahoo, Ask, Bing etc. You must have observed the textbox available for entering the search keywords. We type the keywords and it takes us to the next page where the matched results, fetched from the server, are displayed. When we design a form in HTML to capture data from the user, we use several controls. We can also make a textbox in an HTML form which can behave like a search field and we can perform Google search.
To make such a control, we use <input type=”search”> tag in HTML within the form. It looks like a normal textbox, but it is capable in performing site search.
让我们来看一个基本的SEARCH控件程序。
示例
<html>
<head><title></title>
<script>
function show(){
s=searchForm.searchField.value;
document.write("You have searched for "+s);
}
</script>
</head>
<body>
<form id="searchForm">
<label for="sea">Search for : <label>
<input type="search" name="searchField">
<br><br>
<input type="submit" value="Search" onclick="show()">
</form>
</body>
</html>
这个程序将使用JavaScript代码在下一页上显示搜索到的文本。
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您可能在使用Google时注意到，默认情况下搜索框中会出现一些文本，如下所示：
示例
要做到这一点，我们可以在<input>标签中使用PLACEHOLDER属性。让我们看一个例子。
<html>
<body>
<form id="searchForm">
<label for="sea">Search for : </label>
<input type="search" name="searchField" placeholder="Type URL">
<br><br>
<input type="submit" value="Search" onclick="show()">
</form>
</body>
</html>
VALUE ATTRIBUTE
的中文翻译为：VALUE属性
To set the default value in the search box, you can use VALUE attribute in <input> tag.
这是一个非常有趣的属性，可以在<input>标签中使用，那就是SPELLCHECK属性。此属性可以打开或关闭拼写检查功能。如果它是ON，它将在拼写错误的单词下显示红色波浪线，但如果它是OFF，它将简单地忽略拼写错误。默认情况下，spellcheck属性设置为false。
So, let us see how we can use this attribute.
Example
<html>
<body>
<form id="searchForm">
<label for="sea">Search for : </label>
<input type="search" name="searchField"><br><br>
<input type="submit" value="Search" onclick="show()">
</form>
</body>
</html>
OR
<html>
<body>
<form id="searchForm">
<label for="sea">Search for : </label>
<input type="search" name="searchField" spellcheck=false><br><br>
<input type="submit" value="Search">
</form>
</body>
</html>
In both the cases, the spellcheck attribute is OFF i.e. false. In this situation, it will ignore errors.
Suppose, we entered “Heaith” in the search box whereas the correct spelling is “Health”. But it is not showing any wavy line under the word.
Now let us make it true and see the results.
Example
<html>
<body>
<form id="searchForm">
<label for="sea">Search for : </label>
<input type="search" name="searchField" spellcheck=true><br><br>
<input type="submit" value="Search">
</form>
</body>
</html>
We can also restrict the minimum and maximum number of characters in a search field with the help of MINLENGTH and MAXLENGTH attributes. Suppose in an example, where a user has to type/search admission number for a particular institution, it can accept minimum of 4 characters and maximum of 6 characters. But if you will not put a restriction, a user can type data of any length.
Example
<html>
<body>
<form id="searchForm">
<label for="reg">Type Admission Number : </label>
<input type="search" name="adm" minlength="4" maxlength="6"><br><br>
<input type="submit" value="Search">
</form>
</body>
</html>
It is showing an error on the page because the user has not entered the minimum length of data. And if you try to exceed its maximum limit, it won’t allow to type.
我们还可以通过使用SIZE属性来控制文本框的宽度。而且，我们还可以通过使用REQUIRED属性将其设置为必填字段。
示例
<html>
<body>
<form id="searchForm">
<label for="reg">Type Admission Number : </label>
<input type="search" name="adm" minlength="4"
maxlength="6" size="6" required><br><br>
<input type="submit" value="Search">
</form>
</body>
</html>
观察到盒子的大小现在减小了，如果您将其留空，将显示错误。
