Usage of escape characters in as 3.0 html and xml in as3

When special characters are used in as3, errors may occur accidentally, either the characters are not displayed or the characters are not displayed correctly. In this article, we will make a simple analysis, if you have better analysis, follow up.

Sample. xml and sample_cdata.xml are the xml files used in this example. Please click to view their content. This example uses special characters <and> as an example. The text string variable is txt, the name of the displayed text is shwo_txt.

Because <and> in html and xml have special meanings, they cannot be used directly. When using these two characters, their escape sequences should be used, that is, <and>, therefore, <and> in the xml file will be replaced by & lt; and & gt;. For usage instructions, see sample. xml.

CDATA is used for text data that is not parsed by the xml Parser. In the format of CDATA, the string part is considered a pure string. Even if it contains special characters, it is also considered a common string, for usage, see sample_cdata.xml.

After the xml file is ready, the next step is to use the program to load the xml file and display it in the text box (show_txt) according to the xml content. Here, URLLoader is used for loading. After loading, the string txt is obtained, then, display the information according to the button you clicked. The following is a demo file. "normal" indicates that the xml file of CDATA is not used, and text indicates that the text box does not support html tags, htmlText: html tags are supported (note: flash only supports some html tags ).

As you can see, when xml is normal (CDATA is not used), & lt; and & gt; are first parsed by xml and escaped as <and>, when the text attribute of the string txt is passed to show_txt, because the html tag function is not used, no error occurs and the display result is correct. When the txt is passed to the htmlText attribute of show_txt, because the html tag function is used, special characters <and> are considered invalid characters and are not displayed.

Similarly, when xml uses CDATA to parse text, it considers & lt; and & gt; as simple characters and ignores them, when the txt string is passed to the text attribute of show_txt, & lt; and & gt; are displayed. When the txt string is passed to the htmlText attribute of show_txt, because the html tag function is used, & lt; and & gt; are escaped as <and>, and the result is displayed correctly.

Therefore, both html and xml escape special characters to avoid errors.