格式化银行卡号
<!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>格式化数字</title> <style type="text/css"> #cardNumber { height:50px; width:500px; line-height:50px; font-size:48px; } </style> </head> <body> <input type="text" id="cardNumber" value="" /> <script type="text/javascript"> var cardNum = document.getElementById("cardNumber"); var cardNum_val; cardNum.onblur = checkForm; function checkForm() { cardNum_val = cardNum.value; if(cardNum_val === "") { return false } else if(cardNum_val.length === 16) { for(var i=0; i<cardNum_val.length; i++) { cardNum_val[i] = Number(cardNum_val[i]); if(isNaN(cardNum_val[i])) { alert("请输入数字"); break; } else { formatNumber(cardNum_val); } } } else { return false; } function formatNumber(thisNumber) { var newStr = ""; for(var i=0; i<thisNumber.length; i++) { if(i!==0 && i%4===0) { newStr += " "; } newStr += thisNumber[i]; } cardNum.value = newStr; } } </script> </body> </html>