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JavaScript determines that the input content cannot be all space program code

Source: Internet
Author: User
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In js, spaces and spaces are two different types of conditions. Spaces occupy one character space. Many programmers can directly submit a space if they enter a few spaces during judgment, to filter spaces in js, we only need to use replace for replacement and then judge.

Test instance

1. Only spaces cannot be entered.

The Code is as follows: Copy code

<Input type = "text" onkeyup = "this. value = this. value. replace (/^ + | + $/g,'') ">

2. Do not enter spaces or commas (,) in English.

The Code is as follows: Copy code

<Input type = "text" onkeyup = "this. value = this. value. replace (/[,]/g,'') ">

3,

The Code is as follows: Copy code

<Script type = "text/javascript">
Function myfunction (){
Var a = $ ("text1"). val ();
If ($. trim (a) = ""){
Alert ("cannot be blank! ");
Return false;
}
}
</Script>

Cannot contain all spaces

The Code is as follows: Copy code

<Html>
<Head>
<Script>
Function checkBlankSpace (str ){
While (str. lastIndexOf ("")> = 0 ){
Str = str. replace ("","");
}
If (str. length = 0 ){
Alert ("the input cannot be empty ");
}
}
Function test (){
Var testStr = document. getElementById ("test"). value;
CheckBlankSpace (testStr );
}
</Script>
</Head>
<Body>
<Input type = "text" id = "test"/>
<Input type = "button" value = "test" onclick = "test ()">
</Body>
</Html>

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