JavaScript提供了一种在将表单数据发送到Web服务器之前在客户端计算机上对其进行验证的方法。
基本表单验证包括要检查的表单,以确保填写了所有必填字段。只需要循环遍历表单中的每个字段并检查数据即可。
您可以尝试运行以下代码以在JavaScript中实现基本表单验证-
<html> <head> <title>Form Validation</title> <script> //表单验证 function validate(){ if( document.myForm.Name.value == "" ) { alert( "请提供您的名字!" ); document.myForm.Name.focus() ; return false; } if( document.myForm.EMail.value == "" ){ alert( "请提供您的电子邮件!" ); document.myForm.EMail.focus() ; return false; } if( document.myForm.Zip.value == "" || isNaN( document.myForm.Zip.value ) || document.myForm.Zip.value.length != 5 ) { alert( "Please provide a zip in the format #####." ); document.myForm.Zip.focus() ; return false; } if( document.myForm.Country.value == "-1" ){ alert( "请提供您的国家!" ); return false; } return( true ); } </script> </head> <body> <form action="/cgi-bin/test.cgi" name="myForm" onsubmit="return(validate());"> <table cellspacing = "2" cellpadding = "2" border = "1"> <tr> <td align = "right">Name</td> <td><input type = "text" name = "Name" /></td> </tr> <tr> <td align = "right">EMail</td> <td><input type = "text" name = "EMail" /></td> </tr> <tr> <td align = "right">Zip Code</td> <td><input type = "text" name = "Zip" /></td> </tr> <tr> <td align = "right">Country</td> <td> <select name = "Country"> <option value = "-1" selected>[choose yours]</option> <option value = "1">USA</option> <option value = "2">UK</option> <option value = "3">INDIA</option> </select> </td> </tr> <tr> <td align = "right"></td> <td><input type = "submit" value = "Submit" /></td> </tr> </table> </form> </body> </html>