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This article is to share with you the simple realization of the synchronous display function of mobile phone number and bank card. Interested friends can take a look at
This is an interview question from a certain alliance
Isn’t it all about having a clear idea and then optimizing it while writing
At that time, I said that thinking should be calculated The attribute calculates the value of the preview box based on the content of the input box.
Just handle the focus and blur events.
You have to write by hand. I can’t write by hand. Then the interviewer thought that I would be speechless.
The length of the input content in the input box is greater than 0, and the preview information is displayed
Leave the cursor and close the preview information
Insert a special character_ every 4 digits in the preview information, and the input content remains unchanged
Just use the calculated attribute to judge
<template lang="html"> <p class="zInput"> <p class="big-show" v-show="showBig">{{txt2}}</p> <input type="text" @blur="handerBlur" @focus="handerFocus" v-model="txt"> </p> </template> <script> export default { name: 'z-input', data () { return { txt: '', showBig: false, } }, computed: { txt2: function () { if (this.txt.length > 0) { this.showBig = true } return this.getStr(this.txt, 4) } }, methods: { handerBlur () { this.showBig = false }, handerFocus (evt) { if (evt.target.value.length > 0) { this.showBig = true } }, getStr (str, len) { let lenth = str.length let len1 = len - 1 let newStr = '' for (var i = 0; i < lenth; i++) { if (i % len === len1 && i > 0) { newStr += str.charAt(i) + '_' } else { newStr += str.charAt(i) } } if (newStr.length % (len + 1) === 0) { // 解决最后一位为补充项问题 newStr = newStr.substr(0, newStr.length - 1) } return newStr }, } } </script> <style lang="less"> .zInput{ position: relative; .big-show { position: absolute; top: -40px; font-size: 36px; line-height: 40px; background-color: red; } } .zInput{ top:50px; } </style>
If another length limit is added, the above method is not suitable. The replacement implementation plan v-model
is actually a syntactic sugar
written separately as v-bind:value
andv-on:input
<template lang="html"> <p class="zInput"> <p class="big-show" v-show="showBig">{{txt2}}</p> <input type="text" @blur="handerBlur" @focus="handerFocus" v-bind:value="txt" v-on:input="handerInput"> </p> </template> <script> export default { name: 'z-input', data () { return { txt: '', txt2: '', showBig: false, } }, methods: { handerInput (evt) { let val = evt.target.value.substr(0, 13) // 限制长度13位 this.txt = val evt.target.value = val if (this.txt.length > 0) { this.showBig = true } this.txt2 = this.getStr(this.txt, 4) }, handerBlur () { this.showBig = false }, handerFocus (evt) { if (evt.target.value.length > 0) { this.showBig = true } }, getStr (str, len) { let lenth = str.length let len1 = len - 1 let newStr = '' for (var i = 0; i < lenth; i++) { if (i % len === len1 && i > 0) { newStr += str.charAt(i) + '_' } else { newStr += str.charAt(i) } } if (newStr.length % (len + 1) === 0) { // 解决最后一位为补充项问题 newStr = newStr.substr(0, newStr.length - 1) } return newStr }, } } </script>
Restrict only numbers to be entered
The first thing that comes to mind is to filter out non-numbers when keyup
But The fact is that keydown
->handerInput
->keyup
is executed first, then it will be processed at keydown
, but after keydown modifies evt.target.value
, the
evt.target.value obtained in
handerInput is still unprocessed, so it is said that in
keydownProcessing does not work
Must be processed at
handerInput
<input type="text" @blur="handerBlur" @focus="handerFocus" @keyup="handerKeyup" @keydown="handerKeydown" v-bind:value="txt" v-on:input="handerInput"> <script> handerKeydown (evt) { console.log('handerKeydown') evt.target.value = evt.target.value.replace(/[^\d]/g, '') // 这里修改不起作用 }, handerKeyup (evt) { console.log('keyup') evt.target.value = evt.target.value.replace(/[^\d]/g, '') // 这里执行顺序靠后 修改无用 }, handerInput (evt) { let val = evt.target.value.substr(0, 13).replace(/[^\d]/g, '') console.log('handerInput__val', val) //这里拿到的val是纯数字 evt.target.value = val this.txt = val if (this.txt.length > 0) { this.showBig = true } this.txt2 = this.getStr(this.txt, 4) }, </script>
This is an interview for a certain alliance Question Isn’t it all about having a clear idea and optimizing it while writing
At that time, I mentioned the idea of using calculated properties to calculate the value of the preview box based on the content of the input box
Dealing with focus Just use the blur event
You have to write it by hand, I can’t write it by hand, and then the interviewer thinks I won’t be speechless
<template lang="html"> <p class="zInput"> <p class="big-show" v-show="showBig">{{txt2}}</p> <input type="text" @blur="handerBlur" @focus="handerFocus" v-model="txt"> </p> </template> <script> export default { name: 'z-input', data () { return { txt: '', showBig: false, } }, computed: { txt2: function () { if (this.txt.length > 0) { this.showBig = true } return this.getStr(this.txt, 4) } }, methods: { handerBlur () { this.showBig = false }, handerFocus (evt) { if (evt.target.value.length > 0) { this.showBig = true } }, getStr (str, len) { let lenth = str.length let len1 = len - 1 let newStr = '' for (var i = 0; i < lenth; i++) { if (i % len === len1 && i > 0) { newStr += str.charAt(i) + '_' } else { newStr += str.charAt(i) } } if (newStr.length % (len + 1) === 0) { // 解决最后一位为补充项问题 newStr = newStr.substr(0, newStr.length - 1) } return newStr }, } } </script> <style lang="less"> .zInput{ position: relative; .big-show { position: absolute; top: -40px; font-size: 36px; line-height: 40px; background-color: red; } } .zInput{ top:50px; } </style>If you add a length limit, the above method is not appropriate, change the implementation Solution
v-model is actually a syntactic sugar
written separately as
v-bind:value and
v-on:input
9116fe449ac52b01331f03f825620b05 bd5485bf241f8f25600f58d724cbf170 40dd2db874b79f659b9bd9db3ca6e62e{{txt2}}94b3e26ee717c64999d7867364b1b4a3 3d4998b3e102650fd14aa74928ea3a81 94b3e26ee717c64999d7867364b1b4a3 21c97d3a051048b8e55e3c8f199a54b2 3f1c4e4b6b16bbbd69b2ee476dc4f83a export default { name: 'z-input', data () { return { txt: '', txt2: '', showBig: false, } }, methods: { handerInput (evt) { let val = evt.target.value.substr(0, 13) // 限制长度13位 this.txt = val evt.target.value = val if (this.txt.length > 0) { this.showBig = true } this.txt2 = this.getStr(this.txt, 4) }, handerBlur () { this.showBig = false }, handerFocus (evt) { if (evt.target.value.length > 0) { this.showBig = true } }, getStr (str, len) { let lenth = str.length let len1 = len - 1 let newStr = '' for (var i = 0; i 11acf8853db579d63489c23499573767 0) { newStr += str.charAt(i) + '_' } else { newStr += str.charAt(i) } } if (newStr.length % (len + 1) === 0) { // 解决最后一位为补充项问题 newStr = newStr.substr(0, newStr.length - 1) } return newStr }, } } 2cacc6d41bbb37262a98f745aa00fbf0Limit only numbers can be entered
The first thing that comes to mind is to filter out non-digits during
keyupBut the fact is that
keydown->
is executed first handerInput->
keyup
keydown, but after keydown changes
evt.target.value
The
evt.target.value obtained in
handerInput is still unprocessed, so processing in
keydown does not work
must be done in
handerInputTime processing
<input type="text" @blur="handerBlur" @focus="handerFocus" @keyup="handerKeyup" @keydown="handerKeydown" v-bind:value="txt" v-on:input="handerInput"> <script> handerKeydown (evt) { console.log('handerKeydown') evt.target.value = evt.target.value.replace(/[^\d]/g, '') // 这里修改不起作用 }, handerKeyup (evt) { console.log('keyup') evt.target.value = evt.target.value.replace(/[^\d]/g, '') // 这里执行顺序靠后 修改无用 }, handerInput (evt) { let val = evt.target.value.substr(0, 13).replace(/[^\d]/g, '') console.log('handerInput__val', val) //这里拿到的val是纯数字 evt.target.value = val this.txt = val if (this.txt.length > 0) { this.showBig = true } this.txt2 = this.getStr(this.txt, 4) }, </script>Related recommendations:
Use regular rules to verify the bank card number entered by the user (with code)
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Mobile phone number, email address, ID card, bank card regular verification example
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