javascript——数字验证码

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 1 <script type="text/javascript">

 2         function validateCode() {

 3             var validatevalue = "";

 4             var codes = new Array(4);

 5             var colors = new Array("Red", "Green", "Gray", "Blue", "Maroon", "Aqua", "Fuchsia", "Lime", "Olive", "Silver");

 6             for (var i = 0; i < codes.length; i++) {

 7                 codes[i] = Math.floor(Math.random() * 10);

 8                 validatevalue += codes[i];

 9             }

10             var spans = document.getElementById("divCode").all;

11             for (var i = 0; i < spans.length; i++) {

12                 spans[i].innerText = codes[i];

13                 spans[i].style.color = colors[Math.floor(Math.random() * 10)];

14             }

15             document.getElementById("validatevalue").value = validatevalue;

16         }

17 

18         function validate() {

19             if (document.getElementById("textfield3").value != document.getElementById("validatevalue").value) {

20                 alert("验证码错误");

21                 validateCode();

22                 document.getElementById("textfield3").value = "";

23                 document.getElementById("textfield3").focus();

24                 return false;

25             } else {

26                 return true;

27             }

28         }

29         document.onload = validateCode();

30     </script>