主要介绍了js form表单input框限制20个字符,10个汉字,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友们下面随着小编来一起学习学习吧
直接粘贴到html文件便可看到效果
<!DOCTYPE html> <html> <head> <meta charset=utf-8 /> <meta http-equiv=X-UA-Compatible content=IE=edge /> <meta name=viewport content=width=device-width, initial-scale=1 /> <script src=https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js></script> <script> // 这是第一种最寻常的方法 //定义一个函数 function checkField(value, byteLength, attribute) { // value是input框的值,byteLength是需求限制的字符,attribute是input的id名 var newvalue = value.replace(/[^\x00-\xff]/g, **); var length = newvalue.length; //当填写的字节数小于设置的字节数 if (length * 1 <= byteLength * 1) { return; } var limitDate = newvalue.substr(0, byteLength); var count = 0; var limitvalue = ; for (var i = 0; i < limitDate.length; i++) { var flat = limitDate.substr(i, 1); if (flat == *) { count++; } } var size = 0; var istar = newvalue.substr(byteLength * 1 - 1, 1); //校验点是否为“×” //if 基点是×; 判断在基点内有×为偶数还是奇数 if (count % 2 == 0) { //当为偶数时 size = count / 2 + (byteLength * 1 - count); limitvalue = value.substr(0, size); } else { //当为奇数时 size = (count - 1) / 2 + (byteLength * 1 - count); limitvalue = value.substr(0, size); } alert( 最大输入 + byteLength + 个字节(相当于 + byteLength / 2 + 个汉字)! ); document.getElementById(attribute).value = limitvalue; return; } </script> </head> <body> <div class=wrap> <form> <table class=list-style> <tr> <td style=width:15%;text-align:right;>职业:</td> <td> <input id=profession type=text checkField(this.value,20,'profession') class=textBox length-middle name=profession/> <input id=interest type=text checkField(this.value,100,'interest') class=textBox length-middle name=interest/> <input id=address checkField(this.value,40,'address') type=text class=textBox length-middle name=address /> </td> </tr> </table> <div style=margin:20px 0 0 300px> <button type=reset style=width:60px;height:30px;margin-right:40px refresh()>重置</button> <button type=submit style=width:60px;height:30px return checkNull()>提交</button> </div> </form> </div> </body> </html>