This article mainly introduces the use of JavaScript example code in HTML. Friends who need it can refer to the
##<script> tag<strong></script>
In HTML5, script mainly has the following attributes: async, defer, charset, src, type,- async (optional):
<script src="js/index2.js" async="async"></script>
- #defer (optional):
<script src="js/index1.js" defer="defer"></script>
- charset (optional):
- src (optional):
- type (optional):
Note: When referencing external files, do not add other JS code to the tag. When parsing, the browser will only download the external script file referenced by src, and the code embedded in the table will be ignored. .
## <script>Location of tags<span style="color: #ff0000"><strong> Usually, we place tags with external files (including CSS files , JavaScript files) are placed in the same location, usually inside the <head> tag. </script>
But once multiple JavaScript external files are encountered during the parsing process, the page cannot be fully displayed until all external files are loaded, so usually we will put it in the
tag at the bottom, as shown below:
As mentioned above, there is a defer attribute in <script>, but since it is mentioned in HTML5, HTML5 will ignore it The defer attribute set by the embedded script is currently only supported by IE4~IE7. IE8 will fully follow the HTML5 standard from now on, so placing <script> at the bottom of the <body> tag is still the best choice. </script>
Advantages of referencing external files
- #Easy to maintenance: putting all JavaScript files together not only It does not touch HTML code, and is more conducive to developers writing and maintaining code.
- Accelerate browsing: If multiple HTML pages reference the same JavaScript external file, this file will only be loaded once (cached), which means that the page loading speed can be accelerated.
- Safety: When referencing external files, if the user views the HTML code, they will not see the JavaScript code, which is more secure than writing it in a tag.
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