When limiting the number input by users in js, our core code is to add the onKeyDown event in testarea, and then write a character judgment function to judge the field. value. the length is greater than the character length we set. If yes, substring is truncated.
| The Code is as follows: |
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<Head>
<Title> JavaScript restricts the number of characters in the Textarea text field </title>
<Meta http-equiv = "Content-Type" content = "text/html; charset = gb2312"/>
<Script language = "JavaScript">
<! --//
Function textCounter (field, countfield, maxlimit ){
// Function, three parameters, form name, form field element name, limit character;
If (field. value. length> maxlimit)
// If the number of characters in the element area is greater than the maximum number of characters, it is truncated by the maximum number of characters;
Fieldfield. value = field. value. substring (0, maxlimit );
Else
// Display the remaining characters in the count area text box;
Countfield. value = maxlimit-field. value. length;
}
-->
</SCRIPT>
</Head>
<Body>
<Form name = myform action = "">
<Textarea name = "message" cols = "28" rows = "5" onKeyDown = "textCounter (message, remLen, 6);" onKeyUp =
"TextCounter (message, remLen, 6);"> </textarea>
You can also enter <input name = "remLen" type = "text" value = "6" size = "5" readonly = "readonly"> characters
</Form>
</Body>
</Html> |
Another jquery instance
| The Code is as follows: |
Copy code |
<! DOCTYPE html PUBLIC "-// W3C // dtd xhtml 1.0 Transitional // EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<Html xmlns = "http://www.w3.org/1999/xhtml">
<Head>
<Meta http-equiv = "Content-Type" content = "text/html; charset = UTF-8"/>
<Title> jquery limits the number of words entered and prompts the remaining words </title>
<Script type = "text/javascript" src = "jquery. js"> </script>
<Script type = "text/javascript">
Function words_deal ()
{
Var curLength = $ ("# TextArea1"). val (). length;
If (curLength> 5)
{
Var num = $ ("# TextArea1"). val (). substr (0, 5 );
$ ("# TextArea1"). val (num );
Alert ("when the number of words exceeds the limit, more words will be truncated! ");
}
Else
{
$ ("# TextCount"). text (5-$ ("# TextArea1"). val (). length );
}
}
</Script>
</Head>
<Body>
Remaining <span id = "textCount"> 5 </span> words <br/>
<Textarea name = "textarea" id = "TextArea1" cols = "45" rows = "5" onkeyup = "words_deal ();"> </textarea>
</Body>
</Html> |
