Home > Developer > ASP

Differences between the three methods for outputting JavaScript scripts in ASP. net cs files

Source: Internet
Author: User
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

From: http://cgxcn.blog.163.com/blog/static/132312422009426112839757/

Differences between response. Write and page. clientscript. registerstartupscript and page. clientscript. registerclientscriptblock

 

Method 1, Use response. Write, this method will put JSCodeAt the top of the page (before <HTML> ):
System. Web. httpcontext. Current. response. Write ("<script language = JavaScript> alert ('js Code'); </SCRIPT> ");

Method 2Use registerstartupscript. This method will embed the JS Code at the bottom of the page and before the form (</form>). This method is applicable to the JS Code to run after the page control is loaded:
System. Web. UI. Page page = (system. Web. UI. Page) system. Web. httpcontext. Current. Handler;
If (! Page. clientscript. isstartupscriptregistered (page. GetType (), "clientscript "))
Page. clientscript. registerstartupscript (page. GetType (), "clientscript", "<script language = JavaScript> alert ('js Code'); </SCRIPT> ");

Method 3Use registerclientscriptblock. This method embeds the JS Code at the top of the page and at the beginning of the form (<form>). This method is applicable to the js code to be executed before the control is loaded, similar to the response. write method:
System. Web. UI. Page page = (system. Web. UI. Page) system. Web. httpcontext. Current. Handler;
If (! Page. clientscript. isclientscriptblockregistered (page. GetType (), "clientscript "))
Page. clientscript. registerclientscriptblock (page. GetType (), "clientscript", "<script language = JavaScript> alert ('js Code'); </SCRIPT> ");

 

So what is the difference between method 2 and method 3? The main difference is that,RegisterstartupscriptThe method is to embed Javascript into the bottom of the ASP. NET page, which is exactly at the end of the element.</Form>.RegisterclientscriptblockThe method is to embed Javascript into the page to enable elements.<Form>. So what's the difference? As we will see, this is a big difference.

Here is an example. Here is how to focus on a text box on the page when the page is loaded to the browser-UseRegisterstartupscriptVisual Basic of the method:

Page. clientscript. registerstartupscript (Me. GetType (), "testing", _ "document. Forms [0] ['textbox1']. Focus ();", true)

When the browser runs at the bottom of the page and executes this small JavaScript code, a text box on the page is generated and placed on the page. Therefore, this method runs normally. However, if you do not follow the above method, write the following code (UseRegisterclientscriptblockMethod ):

 
Page. clientscript. registerclientscriptblock (Me. GetType (), "testing", _ "document. Forms [0] ['textbox1']. Focus ();", true)

The text box control does not get the focus and generates a javascript error on the page.

Example:

// Add a script at the top of the page
If ( ! Page. clientscript. isclientscriptblockregistered ( " Myscriptkey " )) // Determine if the same already exists // Key Value scriptblock
{
String Myscript =   @" Function alerthello () {alert ('Hello xuanhun !! ');} " ; // Script content
Page. clientscript. registerclientscriptblock ( This . GetType (), " Myscriptkey " , Myscript, True );

}
// Add a script at the bottom of the page
If ( ! Page. clientscript. isstartupscriptregistered ( " Footscriptkey " ))
{
String Callscript =   @" Alerthello (); " ;
Page. clientscript. registerstartupscript ( This . GetType (), " Footscriptkey " , Callscript, True );
}
// Add references to JS files
If ( ! Page. clientscript. isclientscriptincluderegistered ( " Incluedekey " ))
{
String Includescript =   @" /JS/showhello. js " ;
Page. clientscript. registerclientscriptinclude ( " Includekey " , Includescript );
}

 

 

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More