--- title: "How can you to add JavaScript to a page when performing an asynchronous postback?" description: "How can you to add JavaScript to a page when performing an asynchronous postback?" author: "Amit Singh" published: 2011-03-29 updated: 2020-09-21 canonical: https://www.mindstick.com/interview/711/how-can-you-to-add-javascript-to-a-page-when-performing-an-asynchronous-postback category: "ajax" tags: ["ajax"] reading_time: 1 minute --- # How can you to add JavaScript to a page when performing an asynchronous postback? Use the ScriptManager class. This class contains several methods like the RegisterStartupScript(), RegisterClientScriptBlock(), RegisterClientScriptInclude(), RegisterArrayDeclaration(),RegisterClientScriptResource(), RegisterExpandoAttribute(), RegisterOnSubmitStatement() which helps to add javascript while performing an asynchronous postback. ## Answers ### Answer by Amit Singh Use the ScriptManager class. This class contains several methods like the RegisterStartupScript(), RegisterClientScriptBlock(), RegisterClientScriptInclude(), RegisterArrayDeclaration(),RegisterClientScriptResource(), RegisterExpandoAttribute(), RegisterOnSubmitStatement() which helps to add javascript while performing an asynchronous postback. ### Answer by Varun Agrawal For all three, a script element is rendered after the opening form tag. Following are the differences: \ 1 - RegisterClientScriptBlock - The script is specified as a string parameter. \ 2 - RegisterClientScriptInclude - The script content is specified by setting the src attribute to a URL that points to a script file. \ 3 - RegisterClientScriptResource - The script content is specified with a resource name in an assembly. The src attribute is automatically populated with a URL by a call to an HTTP handler that retrieves the named script from the assembly. --- Original Source: https://www.mindstick.com/interview/711/how-can-you-to-add-javascript-to-a-page-when-performing-an-asynchronous-postback Copyright © MindStick Software Pvt. Ltd. This Markdown version is provided for developers, AI systems, and offline reading.