how i can to make change value textbox by users

Put this in your page and assign it to your textbox:
 

TextBox1.Attributes.Add("onchange", "yourJavaScriptFunction();");

 
change the "TextBox1" to your text box name
Change the "yourJavaScriptFunction()" to the function you want it to hit when the
text of your text box changes.
 
Hope that helps.