Home > Website Builders > Front-end Technology

Commonly used JavaScript limit input character number code

Source: Internet
Author: User
Keywords Web page production Ajax javascript
Tags ajax code content function html http javascript media
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "http://www.jzread.com/TR/xhtml1/DTD/ Xhtml1-transitional.dtd ""
<html xmlns= "http://www.jzread.com/1999/xhtml"
<head>
< Meta http-equiv= "Content-type" content= "HTML; Charset=utf-8 "/>
<style type= text/css Tutorial" media= "screen"
body{margin:0px;
div{width:400px; margin:0px Auto;
Div h3{background: #CCCCCC; font-size:14px; font-weight:bold; text-align:center; line-height:22px; margin:6px 0px; padding:0px;
Div textarea{width:388px height:120px border: #999999 1px solid; margin:0px; padding:0px; font-size:12px; padding : 5px; line-height:16px;
Div p{font-size:12px; margin:0px; line-height:22px;}
Div p span{color: #FF6600; font-weight:bold;}
</style>
<title>javascript Limit the maximum number of characters entered in the text box </title>
</head>

<body>
<div>
<h3> character number Test </h3>
<textarea rows= "cols=" onkeypress= "return Checkmaxlength (this,20)" ></textarea>
<p> Max <span>20</span> characters. </p>
</div>

<script type= "Text/javascript Tutorial" >
function Checkmaxlength (otextarea,maxlength) {
return otextarea.value.length!=maxlength;
}
</script>
</body>
</html>

Programme II

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "http://www.jzread.com/TR/xhtml1/DTD/ Xhtml1-transitional.dtd ""
<html xmlns= "http://www.jzread.com/1999/xhtml"
<head>
< Meta http-equiv= "Content-type" content= "HTML; Charset=utf-8 "/>
<style type=" text/css "media=" screen "
body{margin:0px;
div{width:400px; margin:0px Auto;
Div h3{background: #CCCCCC; font-size:14px; font-weight:bold; text-align:center; line-height:22px; margin:6px 0px; padding:0px;
Div textarea{width:388px height:120px border: #999999 1px solid; margin:0px; padding:0px; font-size:12px; padding : 5px; line-height:16px;
Div p{font-size:12px; margin:0px; line-height:22px;}
Div p span{color: #FF6600; font-weight:bold;}
</style>
<title>javascript Limit the maximum number of characters entered in the text box </title>
</head>

<body>
<div>
<h3> character number Test </h3>
<textarea rows= "cols=" onkeyup= "Checkmaxlength (this,20)" onpaste= "Checkmaxlength (this,20)" ></ Textarea>
<p> Max <span>20</span> characters. </p>
</div>

<script type= "Text/javascript" >
function Checkmaxlength (area, maxLength) {
if (Area.value.length >maxlength) {
Area.value = area.value.substr (0, maxLength);
}
}
</script>
</body>
</html>

Programme III

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "http://www.jzread.com/TR/xhtml1/DTD/ Xhtml1-transitional.dtd ""
<html xmlns= "http://www.jzread.com/1999/xhtml"
<head>
< Meta http-equiv= "Content-type" content= "HTML; Charset=utf-8 "/>
<style type=" text/css "media=" screen "
body{margin:0px;
div{width:400px; margin:0px Auto;
Div h3{background: #CCCCCC; font-size:14px; font-weight:bold; text-align:center; line-height:22px; margin:6px 0px; padding:0px;
Div textarea{width:388px height:120px border: #999999 1px solid; margin:0px; padding:0px; font-size:12px; padding : 5px; line-height:16px;
Div p{font-size:12px; margin:0px; line-height:22px;}
Div p span{color: #FF6600; font-weight:bold;}
</style>
<title>javascript Limit the maximum number of characters entered in the text box </title>
</head>

<body>
<div>
<h3> character test </h3>
<textarea rows= "cols=" Checkmaxlength (this,20) "onpaste=" Checkmaxlength (this,20) ></textarea>
<p> Max <span>20 </span> characters, one character 2 characters. </p>
</div>

<script type= "Text/javascript"
function checkmaxlength (area, maxLength) {
       var currentstr= "";
      for (var i=0,len=area.value.length;i<len;i++) {
            Currentstr+=area.value.charat (i);
           if (getcharlength (CURRENTSTR) >maxlength) {
                  Area.value=area.value.substr (0,i);
                    return;
          }
    }
}

function Getcharlength (str) {
var charlen=0;
for (Var i=0,len=str.length;i<len;i++) {
if (Str.charcodeat (i) >255) {
charlen+=2;
}else{
Charlen+=1;
}
}
return Charlen;
}
</script>
</body>
</html>

Programme III

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "http://www.jzread.com/TR/xhtml1/DTD/ Xhtml1-transitional.dtd ""
<html xmlns= "http://www.jzread.com/1999/xhtml"
<head>
< Meta http-equiv= "Content-type" content= "HTML; Charset=utf-8 "/>
<style type=" text/css "media=" screen "
body{margin:0px;
div{width:400px; margin:0px Auto;
Div h3{background: #CCCCCC; font-size:14px; font-weight:bold; text-align:center; line-height:22px; margin:6px 0px; padding:0px;
Div textarea{width:388px height:120px border: #999999 1px solid; margin:0px; padding:0px; font-size:12px; padding : 5px; line-height:16px;
Div p{font-size:12px; margin:0px; line-height:22px;}
Div p span{color: #FF6600; font-weight:bold;}
</style>
<title>javascript Limit the maximum number of characters entered in the text box </title>
</head>

<body>
<div>
<h3> character test </h3>
<textarea rows= "cols=" Checkmaxlength (this,20) "onpaste=" return false; ></textarea>
<p> Max <span>20</span> characters, one kanji 2 characters, you can also enter <span>20</span> Character </p>
</div>

<script type= "Text/javascript"
var s=document.getelementsbytagname ("span") [1];
function Checkmaxlength (area, maxLength) {
      var currentstr= "";
   if (area.value.length==0) {s.innerhtml=maxlength}
      for (var i=0,len=area.value.length;i<len;i++) {
            Currentstr+=area.value.charat (i);
           if (getcharlength (CURRENTSTR) >maxlength) {
                  Area.value=area.value.substr (0,i);
                    return;
          }else{
              S.innerhtml=maxlength-getcharlengtH (CURRENTSTR);
    }
    }
}

Function Getcharlength (str) {
     var charlen=0
  for (Var i=0,len=str.length;i <len;i++) {
       if (str.charcodeat (i) >255) {
         charlen+=2;
   }else{
        charlen+=1
   }  
 }
  return Charlen
}
</script>
</body>
</html>
 

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
commonly used linux commands commonly used tcp ports commonly used unix commands javascript character code list most commonly used linux commands most commonly used sql commands most commonly used unix commands
Related Article
The input box adapts automatically to the width
Ways to enable IE to support CSS3 fillet
css position usage and cause page deformation JS processing m...
IE8 text-align: center Left-sided solution
How far can DIV + CSS go?
Summarize the compatible code of Firefox and IE browser in CSS

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

Hot Article
Hot Tags
computing conference access forum computer class data get http html applications
Popular Keywords
direct digital landing development documentation data user director of marketing deploy it ddos how to description of products and services ddos information data website domain to dns

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More