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JavaScript input filter showcase
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<!-- https://jsfiddle.net/user/emkey08 --> | |
<!-- https://jsfiddle.net/emkey08/zgvtjc51 --> | |
<h2>JavaScript input filter showcase</h2> | |
<p>Supports Copy+Paste, Drag+Drop, keyboard shortcuts, context menu operations, non-typeable keys, the caret position, different keyboard layouts, and <a href="https://caniuse.com/#feat=input-event" target="_blank">all browsers since IE 9</a>.</p> | |
<p>There is also a <a href="https://jsfiddle.net/emkey08/tvx5e7q3" target="_blank">jQuery version</a> of this.</p> | |
<table> | |
<tr><td>Integer</td><td><input id="intTextBox"></td></tr> | |
<tr><td>Integer >= 0</td><td><input id="uintTextBox"></td></tr> | |
<tr><td>Integer >= 0 and <= 500</td><td><input id="intLimitTextBox"></td></tr> | |
<tr><td>Float (use . or , as decimal separator)</td><td><input id="floatTextBox"></td></tr> | |
<tr><td>Currency (at most two decimal places)</td><td><input id="currencyTextBox"></td></tr> | |
<tr><td>A-Z only</td><td><input id="latinTextBox"></td></tr> | |
<tr><td>Hexadecimal</td><td><input id="hexTextBox"></td></tr> | |
</table> | |
<script> | |
// Restricts input for the given textbox to the given inputFilter. | |
function setInputFilter(textbox, inputFilter) { | |
["input", "keydown", "keyup", "mousedown", "mouseup", "select", "contextmenu", "drop"].forEach(function(event) { | |
textbox.addEventListener(event, function() { | |
if (inputFilter(this.value)) { | |
this.oldValue = this.value; | |
this.oldSelectionStart = this.selectionStart; | |
this.oldSelectionEnd = this.selectionEnd; | |
} else if (this.hasOwnProperty("oldValue")) { | |
this.value = this.oldValue; | |
this.setSelectionRange(this.oldSelectionStart, this.oldSelectionEnd); | |
} else { | |
this.value = ""; | |
} | |
}); | |
}); | |
} | |
// Install input filters. | |
setInputFilter(document.getElementById("intTextBox"), function(value) { | |
return /^-?\d*$/.test(value); }); | |
setInputFilter(document.getElementById("uintTextBox"), function(value) { | |
return /^\d*$/.test(value); }); | |
setInputFilter(document.getElementById("intLimitTextBox"), function(value) { | |
return /^\d*$/.test(value) && (value === "" || parseInt(value) <= 500); }); | |
setInputFilter(document.getElementById("floatTextBox"), function(value) { | |
return /^-?\d*[.,]?\d*$/.test(value); }); | |
setInputFilter(document.getElementById("currencyTextBox"), function(value) { | |
return /^-?\d*[.,]?\d{0,2}$/.test(value); }); | |
setInputFilter(document.getElementById("latinTextBox"), function(value) { | |
return /^[a-z]*$/i.test(value); }); | |
setInputFilter(document.getElementById("hexTextBox"), function(value) { | |
return /^[0-9a-f]*$/i.test(value); }); | |
</script> |
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