TextBox should start with a character and should only contain alphanumeric

Below script helps to bind the user to enter the value in the textbox which starts only with a character and then it may be followed by any alpanumeric characters
To achive this simply follow the following Steps

Write the below javascript function in the aspx page under head section :






In the Body Section of the .aspx page just bind the onClientclick event of the button to the function above in the javascript to check the value of TextBox1

Take one texbox and button control on the page as shown below