Form Text Box Validation

form validation

(function(){
       if(window.addEventListener) window.addEventListener("load",init,false);
       else if(window.attachEvent) window.attachEvent("onload",init);
        
      function init(){
       for(var i=0;i<document.forms.length;i++)
       {
           var f=document.forms[i];//第i个form
           var needValidation = false;// Assume ,for now,that this form does not need any validation
            
           for(var j=0;j<f.elements.length;j++)
           {
               e = f.elements[j];
                
               if(e.type!="text") continue;
               var pattern = e.getAttribute("pattern");
               var required = e.getAttribute("required")!=null;
               //See if it has attribute that require validation
               if(required&&!pattern){
               pattern = "\\s"; 
               e.setAttribute("pattern",pattern);
               }
 
               if(e.pattern){
               e.onchange = validateOnChange;
                
               needsValidation = true;
               }
          }
       if(needValidation) f.onsubmit = validateOnSubmit;
        }
        }
      function validateOnChange()
        {   var textfield = this;
            var pattern = textfield.getAttribute("pattern");
            var value = textfield/*this*/.value;
             
            if(value.search(pattern)==-1) textfield.classname = "invalid";
            else textfield.classname = "valid";
        }
      function validateOnSubmit()
        {
            var invalid = false;
            for(var i=0;i<this.elements.length;i++)
               {
                  var e = this.elements[i];
                  if(e.type =="text" && e.onchange == validateOnChange){
                    e.onchange();
                    if(e.classname == "invalid") invalid = true;
                   }
                }
            if(invalid){
             alert("The form is incompletely or incorrectly filled out.\n "+"Please correct the highlighted field and try again");
             return false;
            }
        }
})();

transfer:

<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style >
    input.invalid { background-color:#fa0;}
</style>
</head>
 
<body>
<form action="test.asp">
Name:<input type="text" name="name" required  /><br />
email:<input type="text" name="email" pattern="^\s*\w+@\w+\.\w+\s*$" /><br />
zipcode:<input type="text" name="zip" pattern = "^\s*\d{5}\s*$" /><br>
unvalidated:<input type="text" onchange='alert("test")' /><br />
<input type="submit" />
</form>

025_ results

Form Text Box Validation

form validation

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