63 lines
1.5 KiB
HTML
63 lines
1.5 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta http-equiv="X-UA-Compatible" content="ie=edge">
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<title>输入框输入限制</title>
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<style>
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.main,
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textarea {
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width: 403px;
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height: 256px;
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}
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.main {
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position: relative;
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}
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.result {
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position: absolute;
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right: 0;
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bottom: 0;
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}
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.error {
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color: red;
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}
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</style>
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</head>
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<body>
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<div class="main">
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<textarea oninput="checkNumber()" id="UserMessage" class="zhangsan" name="" cols="30" rows="10" placeholder="请输入留言"></textarea>
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<div class="result">200 / 200</div>
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</div>
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<script>
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// var 变量 ， let
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// const 常量
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// var username = "zhangsan"
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// username = "zhangsan"
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var UserMessage = document.getElementById("UserMessage");
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var Result = document.getElementsByClassName("result")[0];
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var TotalNumber = 200;
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function checkNumber () {
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var YourMessage = UserMessage.value;
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if(YourMessage.length > 200) {
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UserMessage.value = YourMessage.substring(0,200);
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Result.innerHTML = `超过限制 / 200`;
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Result.className = "result error";
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}else {
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Result.innerHTML = `${TotalNumber - YourMessage.length} / 200`;
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Result.className = "result";
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}
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//Result.innerHTML = TotalNumber - YourMessage.length + " / 200"
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}
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</script>
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</body>
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</html> |