Nagz

Validations in Javascript


Email Validations

if (document.formname.fieldname.value.length >0) {
i=document.formname.fieldname.value.indexOf("@")
j=document.formname.fieldname.value.indexOf(".",i)
k=document.formname.fieldname.value.indexOf(",")
kk=document.formname.fieldname.value.indexOf(" ")
jj=document.formname.fieldname.value.lastIndexOf(".")+1
len=document.formname.fieldname.value.length

if ((i>0) && (j>(1+1)) && (k==-1) && (kk==-1) && (len-jj >=2) && (len-jj<=3)) {
}
else {
alert("Please enter an exact email address.\n" +
document.formname.fieldname.value + " is invalid.");
return false;
}

}



Special Characters

var iChars = "!@#$%^&*()+=-[]\\\';,./{}|\":<>?";

for (var i = 0; i < document.formname.fieldname.value.length; i++) {
if (iChars.indexOf(document.formname.fieldname.value.charAt(i)) != -1) {
alert ("Your username has special characters. \nThese are not allowed.\n Please remove them and try again.");
return false;
}
}


Check if certian radio buttons have not been selected.

if (!document.formname.fieldname[0].checked &&
!document.formname.fieldname[1].checked &&
!document.formname.fieldname[2].checked &&
!document.formname.fieldname[3].checked) {
alert("Please choose a group designation.\n");
return false;
}


Check if textbox has any characters in it.
if (document.formname.fieldname.value.length == 0) {
alert("Please fill out your name.\n");
return false;
}

Check if multiple checkboxes have not been selected.Replace false with true to see if all are selected.


if (document.formname.fieldname.checked == false &&
document.formname.fieldname.checked == false &&
document.formname.fieldname.checked == false) {

alert("Please select at least one checkbox.\n");
return false;
}


Check drop down has been selected. Set drop down's value to Not_Selected for this to work

if (document.formname.fieldname.value == 'Not_Selected') {
alert("Please provide us with a selection.\n");
return false;
}


Scan values in a field and if they are all letters then alert. The second block of code does the same but for numbers

//alert on finding all letters
var noalpha = /^[a-zA-Z]*$/;
if (noalpha.test(document.formname.fieldname.value)) {
alert("Please enter at least one number in the \"username\" field.");
return false;
}

//alert on finding all numbers
var nonums = /^[0-9]*$/;
if (nonums.test(document.formname.fieldname.value)) {
alert("Please enter at least one letter in the \"username\" field.");
return false;
}



Remove special characters from a string.

function clearText() {
document.formname.fieldname.value=filterNum(document.formname.fieldname.value)

function filterNum(str) {
re = /\$|,|@|#|~|`|\%|\*|\^|\&|\(|\)|\+|\=|\[|\-|\_|\]|\[|\}|\{|\;|\:|\'|\"|\<|\>|\?|\||\\|\!|\$|\./g;
// remove special characters like "$" and "," etc...
return str.replace(re, "");
}
}

posted by Nagz @ 11:26 AM