entering numbers only

hi experts..
i have form with text box and i want to make user enter numbers only, when user enters non numbers an error  message should appear.
any idea ?
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<INPUT type="text" name="numeric" maxlength="8"  onkeyup='this.value=this.value.replace(/[^\d]*/gi,"");' />
The above will prevent the user from entering non-numeric characters, so there is no need for an error message box.
James RodgersWeb Applications DeveloperCommented:
what knight gave you will replace/delete any non-numeric value

if you want an alert

<INPUT type="text" name="numeric" maxlength="8"  onkeyup='if(!(/\d/gi).test(this.value)){alert("Invalid Chracter");this.value=this.value.replace(/[^\d]*/gi,"");}' />

also uses the replace from knight

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James RodgersWeb Applications DeveloperCommented:
or in a function
function numericOnly(objText, iFlag){
            alert("Invalid Character");


can be call from any input as

<INPUT type="text" name="numeric" maxlength="8"  onkeyup="numericOnly(this,1)">
give alert


<INPUT type="text" name="numeric" maxlength="8"  onkeyup="numericOnly(this,0)">

no alert
James RodgersWeb Applications DeveloperCommented:
thans for the points
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