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ASP FAQ Tutorials :: Classic ASP 1.0 :: Forms :: What is the limit on QueryString / GET / URL parameters?
What is the limit on QueryString / GET / URL parameters?
RFC 2068 states:
Note that there is no limit on the number of parameters you can stuff into a URL, but only on the length it can aggregate to.
Keep in mind that the number of characters will be significantly reduced if you have special characters (e.g. spaces) that need to be URLEncoded (e.g. converted to the sequence '%20'). For every space, you reduce the size allowed in the remainder of the URL by 2 characters - and this holds true for many other special characters that you may encode before sending the URL to the client.
Keep in mind, also, that the SGML spec declares that a URL as an attribute value (e.g. <a href='{url}'>) cannot be more than 1024 characters. Similarly, the GET request is stored in the server variable QUERY_STRING, which can have similar limitations in certain scenarios.
If you are hitting a limit on length, you should consider using POST instead of GET. POST does not have such low limits on the size of name/value pairs, because the data is sent in the header, not in the URL. The limit on POST size, by default, is 2 MB on IIS 4.0 and 128 KB on IIS 5.0. POST is also a little more secure than GET -- it's tougher (though not impossible) to tinker with the values of POSTed variables, than values sitting in the querystring.
See Article #2223 for more information on using POST to overcome limitations on length.
- Servers should be cautious about depending on URI lengths above 255 bytes, because some older client or proxy implementations may not properly support these lengths.
Note that there is no limit on the number of parameters you can stuff into a URL, but only on the length it can aggregate to.
Keep in mind that the number of characters will be significantly reduced if you have special characters (e.g. spaces) that need to be URLEncoded (e.g. converted to the sequence '%20'). For every space, you reduce the size allowed in the remainder of the URL by 2 characters - and this holds true for many other special characters that you may encode before sending the URL to the client.
Keep in mind, also, that the SGML spec declares that a URL as an attribute value (e.g. <a href='{url}'>) cannot be more than 1024 characters. Similarly, the GET request is stored in the server variable QUERY_STRING, which can have similar limitations in certain scenarios.
If you are hitting a limit on length, you should consider using POST instead of GET. POST does not have such low limits on the size of name/value pairs, because the data is sent in the header, not in the URL. The limit on POST size, by default, is 2 MB on IIS 4.0 and 128 KB on IIS 5.0. POST is also a little more secure than GET -- it's tougher (though not impossible) to tinker with the values of POSTed variables, than values sitting in the querystring.
See Article #2223 for more information on using POST to overcome limitations on length.
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