how to bring a file from a url and store it in a variable in javascript(EXTjs)?

how to开发者_JAVA技巧 bring a file from a url and store it in a variable?

using text fields, such as FOLLOWS:

new Ext.form.TextField({
           disabled: false,
                        fieldLabel: "url",
                        value:'',
   id:"url1"
   }));

A user inserts a url in the respective fields, I need to save the file on the url in a temporary variable.

Thanks for your answers

Pull the URL into a hidden IFrame and access it from there?

The URL could point to anything, from HTML, XML, plain text, or binary data. If you are more specific about what the URL will contain then maybe someone can give a more specific answer.