Google地球KML中的文字叠加(Text Overlay in Google Earth KML)

 最简单的方法是使用HTML5 pattern属性 ： 
 
 
 
 
 
  
<style>
:invalid { border-color: red }
</style>
<form>
<label for=uname>Username:</label>
<input id=uname name=uname type=text pattern="XYZ.*">
<p><input type=submit value=Submit>
</form>
 
 
 
 
 
 该示例使用CSS来指示带有红色边框的无效字段，以用于说明。 
 
 代码接受任何以XYZ（区分大小写）开头的字符串，包括字符串XYZ。 根据需要修改。 
 
 由于不普遍支持pattern属性，因此您可能希望添加执行类似检查的JavaScript代码。 在其中，使用正则表达式（如pattern属性）是最简单的方法。 

The simplest way is to use the HTML5 pattern attribute:
 
 
 
 
 
  
<style>
:invalid { border-color: red }
</style>
<form>
<label for=uname>Username:</label>
<input id=uname name=uname type=text pattern="XYZ.*">
<p><input type=submit value=Submit>
</form>
 
 
 
 
 
The example uses CSS to indicate an invalid field with red border, for illustration.
 
The code accepts literally any string that starts with XYZ (case-sensitively), including the string XYZ. Modify as needed.
 
Since the pattern attribute is not universally supported, you probably want to add JavaScript code that performs a similar check. In it, using a regular expression, as in a pattern attribute, is the simplest approach.