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Old April 28th, 2008, 12:58 PM
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Default validate email address

Hi all,
I've got some javascript to validate entries on a webform. It checks to make sure that each required field has something in it. I would like to also validate that the email address at least looks like a valid one. Here's the javascript:

    <script type="text/javascript">
        function checkform(of)
        // Test if DOM is available and there is an element called required
            if(!document.getElementById || !document.createTextNode){return;}

        // Define error messages and split the required fields
            var errorID='errormsg';
            var errorClass='error'
            var errorMsg='Please enter or change the fields marked with a ';
            var errorImg='alert.gif';
            var errorAlt='Error';
            var errorTitle='This field has an error!';
            var reqfields=document.getElementById('required').valu e.split(',');

        // Cleanup old mess
            // if there is an old errormessage field, delete it
                var em=document.getElementById(errorID);
            // remove old images and classes from the required fields
            for(var i=0;i<reqfields.length;i++)
                var f=document.getElementById(reqfields[i]);
                if(f.previousSibling && /img/i.test(f.previousSibling.nodeName))
        // loop over required fields
            for(var i=0;i<reqfields.length;i++)
        // check if required field is there
                var f=document.getElementById(reqfields[i]);
        // test if the required field has an error,
        // according to its type
                    case 'text':
                        if(f.value=='' && f.id!='email'){cf_adderr(f)}
        // email is a special field and needs checking
                        if(f.id=='email' && !cf_isEmailAddr(f.value)){cf_adderr(f)}
                    case 'textarea':
                    case 'checkbox':
                    case 'select-one':
                        if(!f.selectedIndex && f.selectedIndex==0){cf_adderr(f)}
            return !document.getElementById(errorID);

            /* Tool methods */
            function cf_adderr(o)
                // create image, add to and colourise the error fields
                var errorIndicator=document.createElement('img');

            // Check if there is no error message
                // create errormessage and insert before submit button
                    var em=document.createElement('div');
                    var newp=document.createElement('p');
                    newp.appendChild(document.createTextNode(errorMsg) )
                    // clone and insert the error image
                    // find the submit button
                    for(var i=0;i<of.getElementsByTagName('input').length;i++)
                            var sb=of.getElementsByTagName('input')[i];
            function cf_isEmailAddr(str)
                     var at="@"
                                var dot="."
                                var lat=str.indexOf(at)
                                var lstr=str.length
                                var ldot=str.indexOf(dot)
                                if (str.indexOf(at)==-1){
                                    return str.match();

                                if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
                                    return str.match();

                                if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
                                    return str.match();

                                 if (str.indexOf(at,(lat+1))!=-1){
                                    return str.match();

                                 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
                                    return str.match();

                                 if (str.indexOf(dot,(lat+2))==-1){
                                    return str.match();

                                 if (str.indexOf(" ")!=-1){
                                    return str.match();

                      return str.match(/^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/);
                             ***Note this was the original - didn't work.
                             //return str.match(/^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/);

Thanks in advance!

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