How to write Ajax No Refresh to determine whether it is empty or used when registering a user name
This article introduces the relevant knowledge of "how to write Ajax without refresh to determine whether the code is empty or not when registering a user name". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!
The copy code is as follows:
Var xmlHttp
UName () / / when the user name loses focus
{
If (all.uname.== "")
{
All. L1 [XSS _ clean] = "cannot be empty!"
SetTimeout ("close (1)", 1500)
Return
}
Else
{
XmlHttp=new ActiveXObject ("Microsoft.XMLHTTP")
XmlHttp.onreadystatechange=deal; / / callback function
Var url= "aJax.aspx?user='" + all.uname.+ "'"; / / will jump to the page where the user name is detected
XmlHttp.open ("get", url,true); / / submit the form to url in get mode; and start one-step processing
XmlHttp.send (null); / / send
}
}
Deal ()
{
/ / alert (xmlHttp.readystate+ "_ _" + xmlHttp.status)
If (xmlHttp.readystatestatekeeper 4)
{return;}
If (xmlHttp.statusdatabase 200) / / equals 500 is an error in the sql statement or database
{return;}
/ /
Var num = xmlHttp.responseText; / / receive the information sent by the server
/ / alert (num)
All.l1.innerText= ""
If (num > 0)
{
All.l1.innerText= "secondary user name is already in use!"
}
Else
{
All.l1.innerText= "√"
}
}
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