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Determine if input box input is a number

Source: Internet
Author: User
Keywords Web page production Ajax javascript
Tags ajax document function html index javascript script test
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 <html>  

&lt;head&gt; &nbsp; &lt;title&gt; Test number &lt;/title&gt; &nbsp; &lt;script&gt; &nbsp;&nbsp; &nbsp; &nbsp; function Oncheck () {&nbsp; &nbsp; &nbsp; var numvalue=document.getelementbyid ("num"). Value &nbsp; &nbsp; &nbsp; var index=-1 &nbsp; &nbsp; &nbsp; for (Var i=0;i&lt;numvalue.length;i++) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var ch=numvalue.charat (i); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (ch&gt;=0&amp;&amp;ch&lt;=9) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; index=-1 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;}else{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; index=1 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Break; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp;} &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (index==1) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Alert ("The non-numeric you entered!") Please re-enter "); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; document.getElementById ("num") value= ""; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return; &nbsp; &nbsp; &nbsp;}else{&nbsp; &nbsp; &nbsp; alert ("Input correct!") The number you enter is: "+numvalue"; &nbsp;} &NBSp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; function onCheck1 () {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var Numvalue=document.getelementbyid ("Num1"). Value; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (isNaN (NumValue)) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; alert ("Non-digit you entered!") Please re-enter ... "); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; document.getElementById ("NUM1") value= ""; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;}else{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; alert ("Input correct!") The number you enter is: "+numvalue"; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp;} &nbsp; &lt;/script&gt; &nbsp; &lt;/head&gt; &nbsp; &lt;body&gt; &nbsp; &lt;h3&gt; test input is a number the first method &lt;/h3&gt; &nbsp; &lt;input type= "text" id= "num"/&gt; &nbsp; &lt;input "button" value= "Test 1" onclick= "Oncheck ()"/&gt; &nbsp; &lt;h3&gt; test input is a number the second method &lt;/h3&gt; &nbsp; &lt;input type= "text" id= "NUM1" "/&gt; &nbsp; &lt;input type=" button "value="Test 2 "onclick=" OnCheck1 () "/&gt; &nbsp; &lt;/body&gt; &nbsp; &lt;/html&gt; &nbsp;

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Related Keywords:
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