How can I display a message to the user in javascript withou popup alerts or promps

Hi,

 I'm working on asp application with javascript, I was trying to display a message to the user incase he/she enter an invalid value in a textfield, like entring a numeric value in a string field or vice versa without using Alert or Promp popups dut I didn't find any thing.

Is there any way around this and stying at the same page.

 TIA

 Maher
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