Now, let's get down to the truth. I found a lot of ways to restrict text boxes on the Internet, so I had to practice it on my own and practice it. That's right. 
Copy codeThe Code is as follows: function chkPrice (obj ){ 
Obj. value = obj. value. replace (/[^ \ d.]/g ,""); 
// Ensure that the first digit is a number instead of a number. 
Obj. value = obj. value. replace (/^ \./g ,""); 
// Ensure that there is only one and no more. 
Obj. value = obj. value. replace (/\. {2,}/g ,"."); 
// Ensure that the message appears only once, but not more than twice. 
Obj. value = obj. value. replace (". "," $ # $ "). replace (/\. /g ,""). replace ("$ # $ ",". "); 
} 
Function chkLast (obj ){ 
// Truncates an invalid character. 
If (obj. value. substr (obj. value. length-1), 1) = '.') 
Obj. value = obj. value. substr (0, (obj. value. length-1 )); 
} 
The following is the text box to be called:Copy codeThe Code is as follows: <input type = "text" name = "txt0000" id =" txt0000" class = "common" onkeyup = "chkPrice (this ); "onblur =" chkLast (this) "onpaste =" javascript: return false; "/>
 
At last, onpaste = "javascript: return false;" is used to disable the "Paste" menu by right-clicking the mouse to prevent the right-clicking or Ctrl + V from pasting invalid data.
 
I have tested the above JavaScript code only in the IE8 environment. If you have any ideas or questions, please leave a message.