Javascript 如何防止javascript中的非字母数字输入？
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How to prevent non-alphanumeric input in javascript?
提问by Alegro
$("#user").keyup(function(e){
var regx = /^[A-Za-z0-9]+$/;
if (!regx.test('#user'))
{$("#infoUser").html("Alphanumeric only allowed !");}
);}
#useris a text input, and I want to diplay a warning if user enters anything except letters and numbers.
In the above case, the warning is present whatever is typed.
#user是文本输入，如果用户输入字母和数字以外的任何内容，我想显示警告。
在上述情况下，无论键入什么都会出现警告。
回答by Sudhir Bastakoti
change:
改变：
if (!regx.test('#user'))
to
到
if (!regx.test( $(this).val() ) )
Do:
做：
$("#user").keyup(function(e){
var str = $.trim( $(this).val() );
if( str != "" ) {
var regx = /^[A-Za-z0-9]+$/;
if (!regx.test(str)) {
$("#infoUser").html("Alphanumeric only allowed !");
}
}
else {
//empty value -- do something here
}
});
JS Fiddleexample
JS小提琴示例
回答by Nanne
THis line
这条线
regx.test('#user')
has you testing the string #user, and that is a string that has a bad character (the #). So it will always say not allowed.
您是否测试了 string #user，这是一个包含错误字符 (the #)的字符串。所以它总是说不允许。
Use the actual value of your $("#user")there by using $(this).val()
使用你$("#user")那里的实际价值$(this).val()
回答by HosseiN
You must test with #user element value not '#user' string
您必须使用 #user 元素值而不是 '#user' 字符串进行测试
$("#user").keyup(function(e){
var regx = /^[A-Za-z0-9]+$/;
if (!regx.test($('#user').val())) // .
{$("#infoUser").html("Alphanumeric only allowed !");}
);}
回答by Deenathaiyalan Shanmugam
$('#alpha').bind('keypress', function (event) {
var regex = new RegExp("^[a-zA-Z\b]+$");
var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
if (!regex.test(key)) {
event.preventDefault();
return false;
}
});
$('#numeric').bind('keypress', function (event) {
var regex = new RegExp("^[0-9\b]+$");
var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
if (!regex.test(key)) {
event.preventDefault();
return false;
}
});
$('#alphanumeric').bind('keypress', function (event) {
var regex = new RegExp("^[a-zA-Z0-9\b]+$");
var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
if (!regex.test(key)) {
event.preventDefault();
return false;
}
});
$('#alphanumericspecial').bind('keypress', function (event) {
var regex = new RegExp("^[a-zA-Z0-9 .]+$");
var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
if (!regex.test(key)) {
event.preventDefault();
return false;
}
});
回答by rai.skumar
function isNotAlphanumeric(){
return (! val.match(/^[a-zA-Z]+$/))
//return val.match(/^[a-zA-Z0-9]+$/) ? false : true;
}
so if val is alpha numeric it return false. So based on returned value take appropriate action. You can call this method on key up event.
因此，如果 val 是字母数字，则返回 false。所以根据返回值采取适当的行动。您可以在 key up 事件上调用此方法。
