Skip to main content

document.write

David Greenberg
  • Updated

    document.write (DW): 

    • Executes where encountered by User 

    • Can be used for adding script elements 

    • Only works while the page is loading; If you call it after the page is done loading, it will overwrite the whole page. 

     

    Why It Is Used: 

    • You can overwrite the entire content in a frame/iframe 

    • Way to embed inline content from an external script (to host/domain)  

    • It is the most reliable way for the content (Widget or Ad) to “know” where the HTML author intends for it to be placed. 

    • Scripts can have a negative impact on page performance and modern browsers have taken to blocking scripts. DW can be used to inject and bypass these blocks. 

    • It works everywhere, all the time 

     

    Why It Shouldn’t Be Used: 

    • Serializes the rendering engine to pause until external script is loaded. This could take much longer to load than an internal (none-DW) script. 

    • Browser must download, parse, and execute the first external JavaScript resource before it executes the document.write() that fetches the additional external resources.  

    • No single script should have the right to control (alter) a page before it’s ready to be viewed  

     

    Common Examples: 

    • Twitter Stream 

    • Google Analytics 

     

    What We Could Do To Improve User Experience with Tag Auditor: 

    • Look for DW in the code 

    • Make a note in the Db (Flag) 

    • When a Tag is seen firing from a Tag Manager AND placed directly on the site 

    • Cross reference the flag 

    • Display a option to show with/without DW Relationship(s) 

    • Like New Tag & Non-Secure Filters 
       

    What Authors Can Do To Minimize The Use of document.write 

    • Use safer embedding tools like: 

    Related articles

    Comments

    2 comments

    Date Votes

    Please sign in to leave a comment.