Improper Sanitization of Scripts Tags

Greeting All i have a security problem

am developing an asp.net 2.0 application with Ajax 1.0 but am not handling 'Improper Sanitization of Scripts Tags"

 

so any proper solution will be appritiated knowing that this problem would produce asp.net yellow error screen like the one produced in case of submitting a script tag in a user input

 

thanks for your help
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